National Climate Report - May 2012
In early December 2017, due to a sharp, but real, increase in temperature during the 21st century at Barrow (Utqiaġvik), NCEI's quality assurance algorithms retroactively rejected the station's monthly temperatures dating to late summer 2016. Because the Barrow temperature was not considered, it resulted in an underestimate of recent monthly temperatures for Alaska Climate Division 1 and to a lesser extent the Alaska statewide average. NCEI is working to correct this issue in the coming weeks. The station's daily data are available and correct in Global Historical Climatology Network – Daily (GHCN-D).
Maps and Graphics
Temperature and Precipitation Ranks
U.S. Percentage Areas
Supplemental May and January-May Information
- Year-to-date temperature evolution for select U.S. cities
- State-by-State: Warmest Seasons and January-May
- Supplemental temperature and precipitation graphics
- Warmest 12-month periods for contiguous U.S.
- Spring daily temperature extremes
- Pre-Hurricane season tropical cyclones
- Climate Highlights — spring (March-May)
- The national temperature of 57.1 degrees F during spring was 5.2 degrees F above the long-term average, besting the previous warmest spring of 1910 by 2.0 degrees F. This marked the largest temperature departure from average of any season on record for the contiguous United States. The spring of 2012 was the culmination of the warmest March, third warmest April, and second warmest May. This marks the first time that all three months during the spring season ranked among the ten warmest, since records began in 1895.
- Record and near-record warmth dominated the eastern two-thirds of the nation during spring. Thirty-one states were record warm for the season, and 11 additional states had spring temperatures ranking among their ten warmest. Only Oregon and Washington had spring temperatures near their average.
- Spring was drier than average for the contiguous U.S. as a whole, with a national precipitation total of 7.47 inches, 0.24 inch below average.
- Wetter-than-average conditions prevailed from the West Coast through the Northern Plains and into the Upper Midwest. Oregon was record wet and Minnesota and Washington were third wettest, compared to their spring histories. The Intermountain West, Ohio Valley, and parts of the Mid-Atlantic were drier than average. Colorado, Utah, Wyoming, Indiana, and Delaware had a top ten dry spring.
- The U.S. Climate Extremes Index (USCEI), an index that tracks the highest and lowest 10 percent of extremes in temperature, precipitation, drought and tropical cyclones across the contiguous U.S., was a record-large 44 percent during the March-May period, over twice the average value. Extremes in warm daytime temperatures (81 percent) and warm nighttime temperatures (72 percent) covered large areas of the nation, contributing to the record high value.
- The warmer-than-average conditions, which persisted through winter and spring, limited snowfall over a large portion of the country. According to the Rutgers Global Snow Lab, the spring snow cover extent across the contiguous U.S. was the third smallest on record.
- A list of select May and spring temperature and precipitation records can be found here.
- Climate Highlights — May
- The average temperature for the contiguous U.S. during May was 64.3 degrees F, which is 3.3 degrees F above average — the second warmest May on record
- Warmer-than-average temperatures were present for all regions except the Northwest, with the largest departures from average across the Central Plains, Midwest, and Northeast. Twenty-six states had May temperatures ranking among their ten warmest.
- Precipitation patterns across the contiguous U.S. were mixed during May. The Eastern Seaboard and Upper Midwest were wetter than average. North Carolina, South Carolina, Vermont, New Hampshire, and Minnesota had May precipitation totals among their ten wettest. Dry conditions prevailed for the Mid-South, parts of the Southern Plains, and the Great Basin. Arkansas, Missouri, Kansas, Nevada, and Utah had a top ten dry May.
- Tropical Storm Beryl made landfall near Jacksonville, Florida on May 28th, bringing beneficial rainfall to parts of the drought-stricken Southeast. Beryl occurred on the heels of Tropical Storm Alberto, marking only the third time on record that two tropical cyclones reached tropical storm strength during May in the North Atlantic basin.
- Ongoing drought, combined with windy conditions, created ideal wildfire conditions across the Southwest. The Whitewater-Baldy Fire complex in the Gila National Forest of western New Mexico grew out of control and charred over 210,000 acres by the beginning of June. The fire surpassed 2011’s Las Conchas Fire as the largest wildfire on record for the state.
- According to the U.S. Drought Monitor, as of May 29th, 37.4 percent of the contiguous U.S. was experiencing drought conditions, a slight decrease from 38.2 percent at the beginning of May. Drought conditions improved across the coastal Southeast, the Southern Plains, Northeast, and Upper Midwest, while they deteriorated for parts of the Mid-South and Southwest.
- A list of select May and spring temperature and precipitation records can be found here.
- Climate Highlights — Year-to-Date (January-May)
- January-May was the warmest such period on record for the contiguous United States, with an average temperature of 49.2 degrees F, 5.0 degrees F above the long-term average. Twenty-nine states, all east of the Rockies, were record warm for the five-month period and an additional 14 states had temperatures for the period among their ten warmest.
- The year’s first five months brought dry conditions to much of the East. The Southwest to the Central Rockies was also drier than average. Wetter-than-average conditions persisted for the Pacific Northwest, Upper Midwest, and the western Gulf Coast. The national precipitation total for the five-month period was nearly 1.0 inch below average.
- For the year-to-date period, the USCEI was a record 43 percent, over twice the long-term average. As with the spring USCEI, the drivers were extremes in warm daytime temperatures (83 percent) and warm nighttime temperatures (70 percent).
- Alaskan temperatures were cooler than average for much of the first five months of 2012. The state had its 15th coolest January-May period on record, with temperatures 3.2 degrees F below average.
- Climate Highlights — 12-month period (June 2011-May 2012)
- The June 2011-May 2012 period was the warmest 12-month period of any 12 months on record for the contiguous United States. The nationally-averaged temperature of 56.0 degrees F was 3.2 degrees F above the long-term average, surpassing the previous record, set last month (May 2011-April 2012), by 0.4 degrees F. The 12-month period encapsulated the second warmest summer, fourth warmest winter, and the warmest spring on record. Every state across the contiguous U.S. had warmer than average temperatures for the period, except Washington, which was near normal.
- Every state from the Rockies eastward had a top five warmest June-through-May period, and twenty-six states had their warmest such period on record.
Alaska Temperature and Precipitation:
- Alaska had its 22nd coolest May since records began in 1918, with a temperature 2.2°F (1.2°C) below the 1971–2000 average.
- Alaska had its 23rd coolest March-May since records began in 1918, with a temperature 2.7 °F (1.5°C) below the 1971–2000 average.
- Alaska had its 15th coolest January-May since records began in 1918, with a temperature 3.2°F (1.8°C) below the 1971–2000 average.
- Alaska had its 19th wettest May since records began in 1918, with an anomaly that was 19.8 percent above the 1971–2000 average.
- Alaska had its 38th wettest March-May since records began in 1918, with an anomaly that was 10.5 percent above the 1971–2000 average.
- Alaska had its 32nd wettest January-May since records began in 1918, with an anomaly that was 13.1 percent above the 1971–2000 average.
For additional details about recent temperatures and precipitation across the U.S., see the Regional Highlights section below and visit the Climate Summary page". For information on local temperature and precipitation records during the month, please visit NCDC's Records page. For details and graphics on weather events across the U.S. and the globe please visit NCDC's Global Hazards page.
These regional summaries were provided by the six Regional Climate Centers and reflect conditions in their respective regions. These six regions differ spatially from the nine climatic regions of the National Climatic Data Center.
- Northeast Region: (Information provided by the Northeast Regional Climate Center)
- May 2012 was the 14th consecutive warmer-than-normal month in the Northeast. The region’s average temperature of 61.1 degrees F (16.2 degrees C) was 4.8 degrees F (2.6 degrees C) above normal and 2.3 degrees F (1.3 degrees C) warmer than May 2011. It was the warmest May since 1991 and the 5th warmest since 1895. Each of the states in the Northeast averaged on the warm side of normal, with departures that ranged from +2.1 degrees F (1.2 degrees C) in Rhode Island to +6.1 degrees F (3.4 degrees C) in Pennsylvania. The monthly average at eleven of the Northeast states ranked between the third and ninth warmest since 1895; Maine’s average placed that state at 17th warmest in 118 years. Temperature averages for the spring (May-June) of 2012 were also above normal. The Northeast’s average was 50.8 degrees F (10.4 degrees C), which was 5.1 degrees F (2.8 degrees C) above normal. It was the warmest spring since 1895 in the Northeast and in ten of the states. Rhode Island saw its 2nd warmest spring in 118 years and Maine, its third warmest. The year-to-date temperatures were also the warmest since 1895 in the Northeast and in ten states. Maine and Pennsylvania missed the number one spot, but were close each ranked 2nd warmest for this time period.
- After three months of below normal precipitation totals, the Northeast averaged 118 percent of normal in May. Precipitation was not evenly distributed New Hampshire’s total was 157 percent of normal, while Delaware’s was only 49 percent of May’s normal monthly total. For the 118 years of record, New Hampshire ranked 7th wettest, Vermont 9th, and Pennsylvania, 22nd, while Delaware ranked 24th driest. Spring 2012 precipitation totals averaged below normal in the Northeast (91 percent) and in nine of the twelve states in the region. The wetter-than-normal states were Maine, Vermont, and West Virginia, with totals that were 105, 104, and 105 percent of normal, respectively. March through May departures among the drier-than-normal states ranged from 56 percent in Delaware to 98 percent in New Hampshire. State and regional precipitation totals for the January through May time period were all below normal. The Northeast average was 87 percent of normal and state departures ranged from 97 percent in West Virginia to 49 percent in Delaware. It was the driest January through May since 1895 in Delaware, the 3rd driest in Connecticut, the 6th driest in Maryland, and the 10th driest in New Jersey.
- Rainfall during the month resulted in fewer areas of abnormally dry (D0), moderate drought (D1) and severe drought (D2) in the region. The May 27, 2012 U.S. Drought Monitor still had moderate (D1) and severe (D2) drought in Delaware, with pockets of D1 drought in Connecticut, Maryland and Massachusetts. New Jersey, most of New Hampshire and southeastern Maine improved from D1 drought to D0 at month’s end.
- Fruit growers in New York were starting to assess the damage caused by abnormally warm temperatures in March followed by freeze conditions in April. Estimates from Cornell’s Lake Erie Regional Research Laboratory put crop losses for grapes at 40-50%, cherries at 100%, peaches at 90%, and apples at 50%. New York is the second largest apple producer in the country with an economic impact of over $200 million. The actual loss to fruit growers won’t be available until the crop is harvested.
- For more information, please go to the Northeast Regional Climate Center Home Page.
- Midwest Region: (Information provided by the Midwest Regional Climate Center)
- May temperatures were above normal across the Midwest. Temperatures ranged from 1 degree F (1 C) above normal in northwest Minnesota to 7 degrees F (4 C) above normal in eastern Ohio. Preliminary numbers ranked Ohio, Kentucky, Indiana, Michigan, Illinois, Wisconsin, and Missouri among the ten warmest Mays dating back to 1895. Spring temperatures ranked as the warmest on record for all nine Midwest states. Temperatures departures for the March to May season ranged from 4 to 9 degrees F (2 to 5 C) above normal. All nine Midwest states have recorded above normal temperatures for the last seven months or more.
- May precipitation varied with much of the northern third of the Midwest recording above normal precipitation including a large swath of Minnesota that received two to three time normal. The southeast parts of the Midwest were close to normal while much of Missouri, Illinois, Indiana, southern Michigan, and southeast Iowa received only 25 to 75 percent of normal. Spring precipitation was also heaviest across Minnesota with totals ranging from 150 to 200 percent of normal. The driest areas for spring extended from northwest Ohio into Illinois.
- Severe weather reports were down from earlier in the spring, and compared to average for May, but still were widespread. In May, 22 of 31 days had reports of severe weather in the Midwest with no reports on the 8th through the 14th nor on the 16th or 17th. All nine states in the region reported severe weather in both the first and last week of May. All but one of the Midwest tornadoes came in the first six days of the month.
- Drought in Minnesota and northwest Iowa eased with May rains running two to three times normal. Other Midwest locations saw drought worsen as lack of rain, combined with enhanced evapotranspiration, dried out the upper soil layers. Drought conditions worsened in northwest Minnesota and for most of the southern two-thirds of the Midwest. Severe Drought was limited to western Kentucky, extreme southern Illinois, and the boot heel of Missouri but many areas saw drying of the topsoil, stressed plants, and dry lawns as concerns increased about the potential for drought to rapidly worsen.
- The many days of dry conditions in the Midwest allowed farmers to spend more time in the fields, thus corn and soybean planting was running ahead of normal. With much of the crop in the ground by the end of the month, farmers were hoping for adequate rains to replenish soil moisture and supply needed water to stressed plants going into the hot summer months.
- For details on the weather and climate events of the Midwest, see the weekly summaries in the Midwest Climate Watch page.
- Southeast Region: (Information provided by the Southeast Regional Climate Center)
- Mean temperatures in May were generally above average across the Southeast region. The greatest departures were found across parts of Virginia and North Carolina, where monthly temperatures were 4 to 5 degrees F (2.2 to 2.8 degrees C) above average. Temperatures across much of South Carolina, Georgia, Alabama, and northern Florida were 2 to 3 degrees F (1.1 to 1.6 degrees C) above average, while temperatures across south Florida, Puerto Rico, and the U.S. Virgin Islands were near average (i.e. within 1 degree F or 0.5 degrees C) for the month. Several locations recorded one of their warmest May's on record, including Cape Hatteras, NC (2nd warmest), Fort Myers, FL (3rd warmest), Washington D.C. (4th warmest), and Tampa, FL (5th warmest). As in April, the month of May began with record-breaking temperatures across a large part of the region. Over 150 daily maximum and 200 daily high minimum temperature records were tied or broken from the 1st to the 7th of the month. More record-breaking warmth was observed at the end of the month, as temperatures reached 100 degrees F (37.8 degrees C) for the first time this year across southern portions of Alabama and Georgia, as well as across central and northern portions of Florida. Over 200 daily maximum and 250 daily high minimum temperature records were tied or broken from the 25th to the 31st of the month. More than 20 locations recorded their warmest meteorological spring (March-May) on record, including Birmingham, AL, Washington D.C., Tampa, FL, Tallahassee, FL, Atlanta, GA, Columbia, SC, Charleston, SC, Charlotte, NC, Asheville, NC, Raleigh-Durham, NC, Richmond, VA, and Roanoke, VA.
- Monthly precipitation totals were variable across the Southeast region in May. Much of this variability was due to the passage of Tropical Storm Beryl, which dropped between 2 and 7 inches (50.8 and 177.8 mm) of rain across large parts of northeast Florida and eastern sections of Georgia, the Carolinas, and extreme southeastern Virginia, and as much as 10 inches (254 mm) of rain across central portions of the Florida Panhandle, from the 28th to the 31st of the month. This contributed to monthly precipitation totals that ranged between 150 and 300 percent of normal. In addition, several locations across central North Carolina and Virginia, southern Alabama, and south Florida also exhibited above normal precipitation for the month. A disturbance ahead of Beryl dropped nearly 10 inches (254 mm) of rain in Miami, FL on the 22nd of the month, making it one of the wettest 24-hour periods in a record extending back to 1898. Remarkably, the rain gauge at the Miami International Airport recorded 4.4 inches (111.76 mm) in just one hour during the event. This capped off the wettest meteorological spring on record in Miami, FL with 27.49 inches (698.25 mm). Conversely, much of the interior of the Southeast remained dry in May, with monthly precipitation generally less than 50 percent of normal. Monthly precipitation was near normal across most of Puerto Rico and the U.S. Virgin Islands.
- There were 509 reports of severe weather across the Southeast in May, including nine confirmed tornadoes. Four of these occurred in association with Tropical Storm Beryl. In Florida, two homes suffered roof damage from an EF-0 tornado in St. Lucie County, while damage to trees and mangroves was reported when a waterspout moved onshore in Levy County, also resulting in an EF-0 rating. In Orangeburg County, SC, an EF-1 tornado uprooted several trees and destroyed a corn field near the town of Holly Hill. Another EF-1 tornado was confirmed in Carteret County, NC, where at least 60 homes were damaged and three homes were destroyed in the town of Peletier. Four of the remaining five tornadoes in May were rated EF-0, including two waterspouts that moved onshore in Pinellas and Escambia Counties in Florida, while an EF-1 tornado on the 14th of the month blew the roofs off of several homes in the town of Rockingham in Richmond County, NC.
- The Southeast was impacted by two tropical storms in May, marking just the third time since 1851 that two tropical cyclones formed prior to the official start of the Atlantic hurricane season. On the 19th of the month, Tropical Storm Alberto formed off of the Southeast coast, with peak winds of 60 mph (26.8 m/s). The storm produced 3 to 5 foot (0.9 to 1.5 m) waves as well as dangerous rip currents along the North and South Carolina coasts that resulted in several ocean rescues. A little more than a week later, Tropical Storm Beryl made landfall near Jacksonville Beach, FL with peak winds of 70 mph (31.3 m/s), making it the strongest tropical cyclone observed along the Atlantic coast in May in over 100 years. Several thousand customers lost power across northern Florida. In addition to heavy rain and high wind, Beryl contributed to strong rip currents and storm surge flooding along much of the Atlantic coast, which resulted in the death of a teenage boy in Daytona Beach, FL. One other death was confirmed from Beryl when a tree fell on a car along a rural highway in Orangeburg County, SC, killing the driver.
- The rainfall from Tropical Storm Beryl helped alleviate drought conditions across eastern sections of the Southeast. Improvements of one to two drought categories in the U.S. Drought Monitor were noted across parts of the Florida Panhandle, southeastern Georgia, and the coastal plain of the Carolinas. Although the rainfall from Beryl helped extinguish several fires across northern Florida, an estimated 60 fires were still active across 10,000 acres (40.5 sq km) of the state at the end of the month. Crop damage due to hail was reported across several counties in Georgia, including several hundreds of acres of watermelon and other crops that were approaching harvest. The warm, dry weather that persisted across much of the Southeast this spring resulted in reduced wheat yields across Florida, while peach volumes were down between 25 and 35 percent across Georgia due to a lack of accumulated chill hours. On the other hand, several vegetable and commodity crops were able to ship early due to favorable weather conditions.
- For more information, please go to the Southeast Regional Climate Center Home Page.
- High Plains Region: (Information provided by the High Plains Regional Climate Center)
- May 2012 was largely warm and dry across the High Plains Region. The largest temperature departures occurred in southern portions of the Region, where the departures from normal temperature ranged from 4.0-8.0 degrees F (2.2-4.4 degrees C) above normal. The only areas in the Region to have lower than normal temperatures were central and western North Dakota and pockets of Wyoming and South Dakota. Many locations across the Region were ranked in the top 10 warmest Mays on record. For instance, Topeka, Kansas had its 2nd warmest May on record with an average temperature of 71.4 degrees F (21.9 degrees C). The record of 72.7 degrees F (22.6 degrees C) was set back in 1962 (period of record 1887-2012). Many locations set daily records as temperatures soared near the end of the month. Some locations even had their earliest 100 degrees F (37.8 degrees C) day on record. Scottsbluff, Nebraska set a daily record of 100 degrees F (37.8 degrees C) on May 22nd, absolutely crushing the old record of 91 degrees F (32.8 degrees C) set back in 1939 (period of record 1893-2012). Not only was this a new daily record, this was also the earliest 100 degrees F (37.8 degrees C) day on record in Scottsbluff. On average, temperatures there do not reach 100 degrees F (37.8 degrees C) until July 3rd. Prior to this new record, the earliest 100 degrees F (37.8 degrees C) day was May 28th (1934). According to the National Agricultural Statistics Service, the earliest start to the wheat harvest in Kansas since records began in 1952 has occurred this year. By the end of the month, at least 4 percent of the wheat harvest was complete. The earliest harvest prior to this year occurred in 1962 when 1 percent of the crop had been harvested by June 2nd. The dry, hot, and windy weather in Nebraska led to low soil moisture which caused producers to turn on pivots to aid in crop germination. Although rain was a welcome sight to some, the tornadoes and hail that accompanied the storms led to crop damage which will require producers to replant in some areas of Nebraska. This spring (March, April, and May) was a record breaker across the entire High Plains Region. Average temperatures were above normal at all locations in the Region and the largest temperature departures occurred in the east as areas of South Dakota, Nebraska, and Kansas had average temperatures which were over 8.0 degrees F (4.4 degrees C) above normal. Most locations set new records or were at least ranked in the top 5 warmest springs on record. Some of the impressive records include those set in Lincoln, Nebraska and Wichita, Kansas. Lincoln had an average temperature of 59.3 degrees F (15.2 degrees C) which was 8.5 degrees F (4.7 degrees C) above normal and beat its old record of 56.1 degrees F (13.4 degrees C), set in 1977, by 3.2 degrees F (1.8 degrees C) (period of record 1887-2012). Wichita had an average temperature of 64.4 degrees F (18.0 degrees C), which was 9.0 degrees F (5.0 degrees C) above normal and beat its old record of 59.9 degrees F (15.5 degrees C) by a whopping 4.5 degrees F (2.5 degrees C) (period of record 1888-2012).
- May 2012 was dry for much of the High Plains Region. A large area encompassing southern Wyoming, western and southern Nebraska, northern and western Kansas, and the east and west sides of Colorado had precipitation totals which were less than 50 percent of normal. In addition, many locations within that area received only 25 percent or less of normal precipitation and ranked in the top 10 driest Mays on record. Goodland, Kansas had its 2nd driest May on record with only 0.45 inches (11 mm) of precipitation, which was 13 percent of normal precipitation (period of record 1895-2012). The 1927 record held at 0.31 inches (8 mm). Snowpack in Colorado and Wyoming continued to decline. According to the Natural Resources Conservation Service, by the end of the month, the statewide snowpack was just 5 percent of average in Colorado and 22 percent of average in Wyoming. According to the Denver Post, the low snowpack has raised concerns about potential impacts on river recreation in Colorado. Although the majority of the Region was drier than normal, a few areas had above normal precipitation totals including eastern South Dakota, northeastern Nebraska, south-central Colorado, and a few pockets of North Dakota and Wyoming. The highest precipitation amounts were located in eastern South Dakota where totals exceeded 200 percent of normal. Extremely heavy rain fell in eastern South Dakota during the May 5-6 timeframe. The 24-hour precipitation total, ending May 6th, for Madison 2 SE, South Dakota was 4.81 inches (122 mm)! This crushed the old daily record of 3.44 inches (87 mm) set back in 2007 and also set a new 1-day May precipitation record (period of record 1961-2012). The old 1-day precipitation total was 3.79 inches (96 mm), set on May 1, 1972. By the end of the month, this had become the wettest May on record for Madison 2 SE with a total of 9.97 inches (253 mm). The old record of 8.53 inches (217 mm) occurred in 1972. In addition, this also became the wettest month on record for Madison 2 SE, beating out the old record of 9.57 inches (243 mm) which occurred in June 1984. Spring (March, April, and May) precipitation and snowfall totals were some of the lowest on record in the western part of the High Plains Region. A large area of the Region had precipitation totals which were 25-50 percent of normal including southern Wyoming, the panhandle of Nebraska, and western and northern Colorado. Some examples of the dryness include Cheyenne, Wyoming and Boulder, Colorado. Cheyenne had its 2nd driest spring on record with only 0.69 inches (18 mm) of liquid equivalent precipitation. This was not far off from the record 0.67 inches (17 mm) which was set in the spring of 1880 (period of record 1871-2012). In addition, Cheyenne had its least snowy spring on record with only 0.6 inches (2 cm) of snowfall. This beat the old record of 3.5 inches (9 cm) which occurred in 2007 (snowfall period of record 1883-2012). Similarly, Boulder, Colorado had its 3rd driest spring with 3.10 inches (79 mm) of precipitation. The record 2.21 inches (56 mm) which fell in 1925 was able to hold on (period of record 1893-2012). Boulder also had its least snowy spring on record with a mere 1.6 inches (4 cm) of snowfall. This easily beat the old record of 3.5 inches (9 cm) which fell in 1982 and was incredibly lower than the average spring snowfall, which in Boulder is 29.5 inches (75 cm).
- There were many changes again to the U.S. Drought Monitor this month. Improvements were made in eastern South Dakota and Nebraska as drought conditions were eliminated due to ample precipitation. Only small areas of abnormally dry conditions (D0) remained there. Moderate drought conditions (D1) were erased from western South Dakota and the majority of western North Dakota as well. Unfortunately, drought conditions elsewhere either emerged or worsened over the course of the month. D1 conditions in eastern North Dakota expanded towards the south. New D0 and patches of D1 have emerged across Kansas. D1 conditions also expanded further across southern Colorado and also across the panhandle of Nebraska and into southern Wyoming and northwestern Colorado. The big story this month was the development of extreme drought conditions (D3) in northwestern Colorado due to extremely low precipitation. According to the U.S. Seasonal Drought outlook released on May 17th, drought conditions were expected to improve in areas of North Dakota and the panhandle of Nebraska. Drought conditions in Colorado, southern Wyoming, and southwestern Kansas were expected to persist.
- For more information, please go to the High Plains Regional Climate Center Home Page.
- Southern Region: (Information provided by the Southern Regional Climate Center)
- As was the case in the past few months, the Southern Region experienced yet another warmer than normal month in May. Temperature values were slightly higher in the northern half of the region, ranging from 4 to 8 degrees F (2.22 to 4.44 degrees C) above normal, while in the southern half of the region, values ranged from approximately 2 to 4 degrees F (1.11 to 2.22 degrees C) above normal. Arkansas, Oklahoma and Tennessee had the highest state temperature rankings in the region. Arkansas experienced its fourth warmest May on record, with a state average temperature of 73.10 degrees F (22.83 degrees C). For Oklahoma, it was the fifth warmest May on record (1895-2012), while for Tennessee, it was their sixth warmest May on record (1985-2012). Oklahoma had a state wide temperature average of 72.20 degrees F (22.30 degrees C), while Tennessee had a state wide temperature average of 70.40 degrees F (21.33 degrees C). Temperature rankings were also high in the three remaining states. Texas experienced its eleventh warmest May on record (1895-2012) with a state average temperature of 75.40 degrees F (24.11 degrees C). In Louisiana, the state average temperature was 76.00 degrees F (24.44 degrees C) or the twelfth warmest May on record (1895-2012). Mississippi had its fourteenth warmest May on record (1895-2012) with a state average temperature o f 74.00 degrees F (23.33 degrees C).
- With the exception of southwestern Texas, May was a rather dry month for the bulk of the Southern Region. Precipitation was scarce in the central portions of the region where most stations recorded less than one fourth of the normal monthly totals. This was also the case for most of the Texas and Oklahoma panhandle region. Elsewhere, values ranged mostly between twenty-five and fifty percent of normal. Southwestern Texas was the only portion of the region that observed above normal rainfall, with precipitation totals ranging from one and one half to four times of normal. Despite that, Texas' state wide precipitation average was slightly on the dry side with a total of 2.81 inches (71.37 mm). Arkansas, Oklahoma and Louisiana had the highest state-wide precipitation rankings. For Oklahoma, which received a total of 2.33 inches (59.18 mm), it was the eleventh driest May on record (1895-2011). It was the second driest May on record in Arkansas, which saw only 1.63 inches (41.40 mm) of precipitation. Louisiana averaged 2.26 inches (57.40 mm) of precipitation, which makes it their fifteenth driest May on record (1895-2012). For Mississippi, it was the thirty-third driest May on record, which is based on a state-wide precipitation total of 3.05 inches (77.47 mm). Lastly, Tennessee experienced its twenty-eighth driest May on record, with a state wide precipitation total of 3.26 inches (82.80 mm).
- Consistent dryness over much of the Southern Region has led to an expansion of drought in some areas, while above average precipitation has led to improvements in other areas. In the case of the latter, high precipitation in southwestern Texas, has led to the removal of all exception drought in that portion of the state. Though moderate drought remains, this is a significant improvement over last month, where most of the area was riddled with severe to extreme drought. In northern Arkansas, where precipitation was below normal for much of the month, there has been an introduction of moderate drought. This also includes portions of northeastern Mississippi and western Tennessee, where conditions were also drier than normal over the past several weeks.
- On May 10, 2012, over a dozen tornadoes touched down in southern Texas. In La Salle County, two people were reported injured.
- For more information, please go to the Southern Regional Climate Center Home Page.
- Western Region: (Information provided by the Western Regional Climate Center)
- May is typically a month in which temperatures increase and precipitation totals have begun to wane in the coastal and southern West as the Pacific storm track edges northward and the Southwest Monsoon system has yet to develop. May 2012 showed few exceptions to this trend. Many Southwest locations received no precipitation at all, and only a smattering of stations in the Northwest and along the Mexico border recorded average to above-average precipitation. The northern tier of the region experienced cooler than normal average temperatures this month, while in the Southwest, average temperatures were generally above the May mean. Severe fire weather dominated the Southwest, leading to the rapid development of several large wild land fires and New Mexico experiencing its largest fire on record.
- Many locations the Southwest were dry this month, not uncommon in Mays past. For the 31st time in the last 75 years, Las Vegas, Nevada received no measureable precipitation (less than 0.01 in / 0.25 mm) in May. Further west, Santa Barbara, California has 25 years in its 71-year record with no measurable May precipitation. Other zero-precipitation locations this month include Yuma and Flagstaff, Arizona and Palm Springs, California. To the north, central Washington and Oregon have seen drought development over the last few months. This month, Spokane, Washington received only 0.69 in (17.5 mm) rainfall, the 28th driest May in the station’s 112-year record. Western Washington and Oregon fared better, with Seattle, Washington and Portland, Oregon notching several daily precipitation records toward month’s end. Rainfall at Portland totaled 3.37 in (85.6 mm), tied for 14th wettest May since records began in 1938. Glasgow, Montana also saw above average precipitation, receiving 3.06 in (77.7 mm) and 11th wettest May in a 57-year record. Mid-month thunderstorm activity along the US-Mexico border helped to alleviate exceptional drought conditions in some specific locations. Las Cruces, New Mexico received 0.58 in (14.7 mm) of rain, tying for the 22nd wettest May in the past 120 years at that location.
- Temperatures in the Northwest and along the coast this month were 2-4 F (1-2 C) below normal, similar to but less cool than May 2010 and 2011. Average May temperatures do not show recent warming or cooling in the Northwest, though the past two years were anomalously cool. The Southwest saw temperatures 2-6 F (1-3 C) above normal, breaking the cool May pattern of 2010 and 2011, and back to the general trend of increasing May temperatures in the Southwest over the past 30 years.
- A significant consequence of the continued warm and dry March, April, and May has been a drastic lowering of the expected summer snowmelt in the Intermountain West. Forecasts of Colorado River inflow to Lake Powell have dropped very far, and now rank among the 3rd or 4th lowest in the past century.
- May (all month): Fires throughout Southwest: Critical fire conditions (low relative humidity, high wind, drought conditions) were in place for most of May in the southwest, allowing wildfires to develop and spread rapidly.
- New Mexico: The Whitewater-Baldy Complex Fire, ignited by lightning on May 16, has become New Mexico’s largest fire on record. As of June 1, 216,650 acres (87,865 hectares) had burned and the fire was only 10% contained.
- Arizona: The Gladiator Fire, approximately 20 mi (32 km) north of Phoenix, Arizona began May 16 and had burned 16,240 acres (6,572 hectares) and was 45% contained as of June 1. The fire was a human-caused structure fire and forced mandatory evacuation of the town of Crown King, Arizona. The Sunflower Fire, 30 mi (48 km) north of Mesa, Arizona began May 12 and had consumed 17,618 acres (7,129 hectares) and stood at 80% contained on June 1.
- Nevada: The Topaz Ranch Estates Fire, 60 mi (97 km) south of Reno, Nevada, began May 22 and burned 7,152 acres (2,894 hectares). The human-caused fire destroyed two residences and 17 structures.
- Colorado: The Hewlett Fire in the Roosevelt National Forest began May 14 and burned 7685 acres (3,110 hectares) before containment. The Sunrise Mine Fire began May 25 4 mi (6 km) north of Paradox, Colorado. By June 1 it had consumed 6,192 acres (2,505 hectares) and was 85% contained. Both fires were human-caused.
- May 26: Four Corners Dust Storm: Southwest winds in excess of 50 mph (80 kph) associated with a deep trough drove a dust storm into the Four Corners region. The dust, combined with smoke from fires in New Mexico, reduced visibility to less than a mile (1.6 km).
- For more information, please go to the Western Regional Climate Center Home Page.
See NCDC's Monthly Records web-page for weather and climate records for the most recent month. For additional national, regional, and statewide data and graphics from 1895-present, for any period, please visit the Climate at a Glance page.
PLEASE NOTE: All of the temperature and precipitation ranks and values are based on preliminary data. The ranks will change when the final data are processed, but will not be replaced on these pages. Graphics based on final data are provided on the Temperature and Precipitation Maps page and the Climate at a Glance page as they become available.