National Overview - July 2009
Maps and Graphics
Temperature and Precipitation Ranks
U.S. Percentage Areas
- Temperature Highlights
- For the contiguous United States the average July temperature of 73.5°F was 0.8°F below the 20th century average and ranked as the 27th coolest July on record, based on preliminary data.
- An abnormally strong and persistent upper-level pattern during the month helped produce a large number of record low temperatures east of the Rockies, while warmth was focused west of the Rockies.
- Four of the seven states that make up the Central U.S. (Ohio, Illinois, Indiana, and West Virginia) experienced their coolest ever July in 115 years of records. The region's three remaining states of Kentucky, Missouri, and Tennessee recorded either their second or third coolest July in history. Pennsylvania also experienced a record cool July, while Wisconsin and Michigan each had its second coolest on record.
- Three western states recorded an average temperature that was much above normal for the month of July: Arizona experienced its third warmest, while New Mexico and Washington each had its ninth warmest July on record.
- Death Valley, California set its all-time monthly average maximum temperature of 121.3°F. Twenty-two days in Death Valley reached 120°F or higher which beat the old record of 19 days.
- For the year-to-date (January - July) period, the contiguous U.S. ranked 28th warmest. New Mexico, Texas, and Colorado experienced their fifth, eighth, and twelfth warmest such periods on record, respectively.
- Based on NOAA's Residential Energy Demand Temperature Index (REDTI), the contiguous U.S. temperature-related energy demand was 13.3 percent below average in July. Much of this low value can be attributed to cooler-than-average conditions in the heavily-populated northeast.
- Precipitation Highlights
- This was the 40th wettest July in the 1895—2009 record. Precipitation across the contiguous U.S. averaged 2.90 inches (74 mm), which is 0.14 inch (4 mm) above the 1901-2000 average.
- The Northeast recorded its ninth wettest July in 115 years of record-keeping. Above-normal precipitation also fell in the Central and South regions. In contrast, the Southeast, Southwest, and East North Central regions observed drier-than-normal conditions during the month.
- For the contiguous U.S. as a whole, precipitation was near normal. The above normal averages in the Central and Northeast were counter-balanced by the below normal averages in the Southeast, Southwest, and East North Central regions.
- Massachusetts and Rhode Island both experienced their second and Arkansas its third wettest July on record. Several other states were much above normal including: Maine which experienced its fifth wettest, and Vermont, New Hampshire, and Connecticut each recorded their sixth wettest month.
- By July's end, moderate-to-exceptional drought covered 14 percent of the contiguous U.S., based on the U.S. Drought Monitor. This is one percentage point more than the end of June. Drought conditions worsened in south Texas and northern Wisconsin, and remained largely unchanged in the West and along the border with western Canada.
- About 19 percent of the contiguous United States had moderate-to-extremely wet conditions at the end of July, according to the Palmer Index (a well-known index that measures both drought and wet spell intensity).
- Other Items of Note
- Six states experienced a record cool month in July. The U.S. had not seen a single record cold state, in any month, since August 2004 and there had not been six or more record cold states in a month since July 1992, when there were nine.
- More than 400 record low minimum temperatures and 1,300 record low maximum temperatures (lowest high temperature) were set during July across the nine-state area that makes up the Central region.
- July fire activity was below average, although the year-to-date number of wildfires remains above the 2000-2009 average. For July, 8,515 new wildfires were reported and a total of about 1.7 million acres was burned, primarily in the West and Alaska, according to the National Interagency Coordination Center.
- The Climate Prediction Center (CPC) reported that El Niño conditions were present in the equatorial Pacific Ocean during the month of July. Equatorial sea surface temperatures (SSTs) remained +0.5 to +1.5°C above average across the region at the end of the month. Observations and model forecasts by the CPC indicate El Niño conditions will continue to intensify and are expected to continue through the winter of 2009-2010. For additional information on ENSO conditions, please visit the NCDC ENSO Monitoring page and the latest NOAA ENSO Advisory.
had its 2nd warmest July since records began in 1918, with a
temperature 2.9°F (1.6°C) above the 1971—2000
had its 7th warmest May—July on record, with a
temperature 2.1°F (1.2°C) above the 1971—2000
- Alaska had its 27th warmest January—July on record, with a temperature 0.4°F (0.2°C) 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 May Climate Summary page. For information on local temperature and precipitation records during the month of July, please visit NCDC's Extremes 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)
- The Northeast saw its 3rd coolest July since recordkeeping began in 1895; in addition, it was the coolest July in Pennsylvania and West Virginia. The cool conditions were widespread — each of the remaining states in the region fell within the 18 coolest in 115 years. The Northeast's average temperature of 66.7°F (19.3°C) was 3.0 (1.7°C) below normal and only 0.2 degrees (0.1°C) warmer than the low of 66.5 degrees F (19.2°C) set in 2000. Among the states, departures ranged from 2.1 (1.2°C) below normal in Delaware to 3.9 (2.2°C) below normal in West Virginia. Several stations reported lows in the low to mid 40s (about 4°C) when an unseasonably cool Canadian high pressure system settled over the region between the 12th and 14th. The warmest temperatures occurred a few days later as the winds shifted to the south. A few locations, mostly in the mid-Atlantic area, did manage to reach the mid 90s (about 35°C), but Central Park was not one of them. It was only the second time since 1869 that the mercury failed to reach 90 (32.2°C) in June or July in Manhattan.
- Overall, the Northeast saw 131% of the normal July precipitation, making it the 10th wettest in 115 years. It was not wet throughout the region, however. While Massachusetts and Rhode Island had their 2nd wettest July since 1895, Delaware had its 3rd driest. Maryland was also dry — 72% of normal, and New Jersey (101%) and West Virginia (105%) averaged near normal precipitation. Among individual stations, the monthly totals at Albany, NY (9.91 inches, 25.17 cm) and Providence, RI (10.52 inches, 26.72 cm) established new records for the month of July.
- The lack of adequate rain in Delaware, eastern Maryland and southwestern Pennsylvania caused those areas to fall into the abnormally dry category, according to the July 28, 2009 U.S. Drought Monitor. On the other hand, the August 1, 2009 Long Term Palmer Drought Severity Index indicated extremely moist conditions in most of New England and New York's Hudson Valley. Wet conditions have negatively impacted the agricultural community in these areas. Crop harvesting was behind schedule and disease pressure was high, including concern about late blight affecting the potato and tomato crops.
- Severe weather, with lightning, damaging winds and intense rainfall is fairly common during the summer months in the Northeast. Severe events this month also included at least 3 tornados, 2 in Pennsylvania and one in New Jersey, and numerous reports of .25 to 1 inch (0.6 to 2.5 cm) hail. A storm on the 16th in northern Chittenden County, VT dropped 1-3 inch (2.5 - 7.6 cm) hail over a relatively large area, causing widespread damage. A NWS employee was quick to capture one of the larger stones and Vermont now has a new hailstone record: 3.3 inches (8.4 cm) in diameter. More information on this event can be found here: http://www.westfordweather.net/hail.php.
- For more information, please go to the Northeast Regional Climate Center Home Page.
- Midwest Region: (Information provided by the Midwest Regional Climate Center)
- Temperatures were cool across the Midwest in July. Departures ranged from 2°F (1°C) below normal in eastern Ohio to as much as 6°F (3°C) below normal in eastern Iowa. Most of the Midwest remained below normal throughout July with only occasional excursions above normal. For the entire Midwest in July, only one record high temperature was recorded along with 18 record high minimum temperatures. On the other hand, there were more than 400 record low temperatures and more than 1300 record low maximum temperatures during the month. Two periods were particularly cool, July 1-9 and July 17-23. During the former period, 23 record low temperatures and 370 record low maximum temperatures were set or tied. In the latter period, 337 record low temperatures and 942 record low maximum temperatures were set or tied. There was also a drastic reduction in the number of days reaching 90°F (32°C) across the Midwest.
- Preliminary numbers show July 2009 as the coolest on record for the Midwest. Illinois, Indiana, and Iowa also recorded the coolest July on record. Michigan, Ohio, Wisconsin, and Kentucky were the second coolest, while Minnesota was the third coolest and Missouri was the fourth coolest.
- Numerous stations recorded their coolest average July this year. Stations that set July records include International Falls, MN, Madison, WI, Grand Rapids, MI, Flint, MI, Saginaw, MI, Benton Harbor, MI, Dubuque, IA, Cedar Rapids, IA, Rockford, IL, Peoria, IL, Lincoln, IL, South Bend, IN, Fort Wayne, IN, Lima, OH, Cincinnati, OH, Jackson, KY, and Frankfort, KY. The stations broke previous monthly records by up to nearly 4°F (2°C).
- Precipitation varied from below 50% of normal in central Minnesota and most of Wisconsin to as much as 150% of normal in southern Missouri, southern Illinois, western Kentucky, and along the Ohio River. Two additional areas of above normal precipitation were northwest Iowa and along the Mississippi River in eastern Iowa and northwest Illinois. Drought conditions persist across east central Minnesota, the northern two-thirds of Wisconsin, and upper Michigan. An emerging dry area extends from central Ohio into northern Indiana and southern Michigan.
- Crops across the Midwest are developing behind schedule but the reasons vary. Delayed development can be attributed to late planting, dry conditions, and the cool weather in various parts of the region. Some warmer weather would be welcome to accelerate growth but additional water would be needed from Minnesota to Ohio in order to avoid stressing the crops.
- Severe weather has been somewhat dampened by the cool weather in July. On nine days there were a total of 27 tornado reports in the Midwest during July. Lightning caused the only Midwest weather fatality in July when a teenager was struck in Minnesota on July 21st.
- For details on the weather and climate events of the Midwest during May, see the weekly summaries in the MRCC Midwest Climate Watch page.
- Southeast Region: (Information provided by the Southeast Regional Climate Center)
- Mean temperatures for July 2009 were below normal across most of the region. This was especially the case across the northern tier of the region where temperatures in some locations were more than 4°F below normal. This pattern was associated with an unusually persistent upper level trough anchored across the eastern U.S. There were 236 daily record low maximum temperatures set across the region, far exceeding the 78 daily record low temperatures set. This disparity can be tied to an extraordinary number of persistently cloudy days. Roanoke, VA recorded the 3rd lowest mean July temperature in a record extending back to 1948. Temperatures topped 90°F (32°C) there only once during the month. This tied with the fewest occurrences of 90°F (32°C) and greater temperature for the month of July. Asheville NC recorded the 7th lowest mean July temperature in a record extending back to 1902. Montgomery, AL recorded an all time daily minimum temperature on the 9th when the mercury dropped to 59°F (15°C). Mean July temperatures across the southern tier of the region were slightly above normal. Most of the daily record highs in the region were set in FL and southern AL. Dothan and Mobile, AL tied their all time daily record high for July with readings of 105°F (40°C) and 102°F (40°C), respectively, on the 2nd of the month. San Juan, PR reported a monthly mean temperature of 84.8°F (29°C) making it the 3rd warmest July in a record extending all of the way back to 1850.
- Much of the region displayed below normal precipitation totals for the month of July, especially GA and the western panhandle of FL. There was, however, much local scale variability across the region as is typical for the convective active summer months. Precipitation was less than 25 percent of normal across small portions of these regions as well as the Carolinas and VA. Greensboro, NC and Washington, DC recorded slightly over an one inch of precipitation for the month, which registers as the 3rd and 4th driest July in a records extending back to 1903 and 1919, respectively. In contrast, Tarpon Springs, FL recorded over 15 inches (381 mm) of precipitation for the month, which was more than 8 inches (203 mm) above average. Nearly half of this precipitation fell on the 1st of the month. Wilmington, NC and Charleston SC recorded 6.51 inches (165 mm) and 4.15 inches (105 mm) on the 8th of the month as a wave of low pressure moved slowly along a stationary front draped across the region. On the 22nd of the month, thunderstorms dropped over 3 inches (76 mm) of precipitation across portions of Columbia, SC in a 90 minute time frame resulting in much flash flooding.
- For the second straight month, there were no areas of the Southeast displaying drought conditions (D1 or greater) during the month. The dryness over much of the area, however, contributed to an expanding area of abnormally dry conditions (D0) across NC, northern SC and northern GA. State climatologists in the region reported that there are no water supply issues yet; however, dropping reservoir levels are approaching points in which remedial actions may be taken. The dry conditions in GA have aided in the harvesting of hay, however other crops, especially tobacco, are suffering. Recent heavy rainfall in South FL has forced the Army Corp of Engineers to release excess water from Lake Okeechobee. This precautionary move was made to mitigate against flooding impacts if a tropical cyclone passes through the region over the next few months. Low evapotranspiration rates associated with the relatively cool, moist conditions in VA has promoted mold growth. This is having detrimental impact on grape cultivation over portions of the State.
- 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)
- July 2009 went down as the coolest on record for many locations in the High Plains Region as temperatures were 4°F to 6°F (2.2°C to 3.3°C) below normal for much of the Dakotas, Nebraska, and Kansas. Most locations ranked in the top 10 coolest Julys on record and several broke the record. The cool temperatures in Auburn, NE broke a record that has been in place since 1906. The old record of 70.7°F (21.5°C) was just barely edged out by the new record of 70.6°F (21.4°C). Only pockets of Wyoming, Colorado, and Kansas had temperatures above normal.
- Precipitation was hit or miss across the Region this July. Interestingly, the cool temperatures this month did not necessarily accompany above normal precipitation, which would be expected this time of year. The larger areas of below normal precipitation in the eastern side of the Region (eastern North Dakota, eastern Nebraska, and southern Kansas) were all accompanied by cooler temperatures. Small pockets of above normal precipitation occurred in South Dakota, southwest North Dakota, the panhandle of Nebraska, central Wyoming, central Colorado, and eastern Kansas.
- Sporadic precipitation this month led to both improvements and degradation in the U.S. Drought Monitor. Wyoming and nearly all of Colorado are drought free. The largest change to the U.S. Drought Monitor over the past month was to North Dakota and Nebraska. After record precipitation and flooding this spring, a large swath of North Dakota has slipped into abnormally dry conditions and an area of moderate drought has developed in the east central portion of the state. Both abnormally dry conditions and moderate drought conditions have expanded across eastern Nebraska. Meanwhile, much of the abnormally dry conditions in Kansas and South Dakota have been erased. According to the U.S. Seasonal Drought Outlook, the drought conditions in south central Nebraska are expected to improve through October 2009.
- The cool temperatures combined with timely precipitation in Nebraska to produce one of the best wheat crops on record. According to the USDA the average yield has been 48 bushels an acre which is nearly 10 bushels an acre more than usual. Unfortunately, in other parts of the region, there are some concerns about whether or not crops will reach maturity before freezing in the fall.
- The big precipitation story this month comes from Wyoming where, for the first time in nine years, 100% of the state is free of drought or abnormally dry conditions. According to the National Weather Service in Riverton, WY, the drought started as abnormally dry conditions expanded across the state in the late spring and early summer of 2000. The drought peaked in 2003 when 99% of the state was in extreme or exceptional drought. It wasn't until a wet spring in 2005 that Wyoming began to see significant relief and areas of exceptional drought were eliminated. The spring and summer of 2006 were dry and conditions worsened, however above normal precipitation in 2007 helped alleviate drought conditions in the eastern part of the state. Portions of western Wyoming remained in drought until abundant rainfall fell this year. While drought conditions will return, Wyoming is free of drought for now.
- For more information, please go to the High Plains Regional Climate Center Home Page.
- Southern Region: (Information provided by the Southern Regional Climate Center)
- In accordance with what was observed last month, mean July temperatures across the southern region were generally above normal in the south central portions of Texas. Most stations in this area averaged between 2-6°F (1-3°C) above normal. For the remainder of the state, mean temperatures typically averaged within 2°F (1°C) of the expected values. Similar temperature anomalies were also observed in Oklahoma, Louisiana and southern Mississippi. Cooler averages were observed in Tennessee, with most stations averaging between 2-4°F (1-2 °C) below normal. This was also the case for northern Mississippi, central and eastern Arkansas, and northeastern Oklahoma. The coolest average temperatures within the Southern Region were observed in north central Arkansas, where values dipped between 4-8°F (2-4 °C) below normal.
- With the exception of southern Texas, southeast Mississippi and north central Oklahoma, the bulk of the Southern Region received near or above normal precipitation totals for the month. Much of the Southern Region, however; did accumulate rainfall totals that were well above the monthly expected values. In central Texas, rainfall totals ranged between 200 and 300 percent of normal. Similar values were also observed throughout much of central and eastern Arkansas, northwestern Mississippi, and southwestern Tennessee. The driest areas of the Southern region include much of the southern tip of Texas, where extreme and exceptional drought conditions have persisted for weeks.
- Heavy rainfall totals throughout the central portions of the Southern Region have done well to reduce drought conditions. In Oklahoma, the area of moderate drought has been reduced in the central portions of the state. Unfortunately, the dry conditions in the north central area of Oklahoma have led to a slight worsening of drought conditions there. In Central Texas, anomalously high rainfall totals for the month have improved conditions considerably. This was also the case in south central Louisiana. In Southern Texas, conditions have deteriorated to the point where the entire southern tip of the state is now either in extreme or exceptional drought. Collectively, the extreme and exceptional drought conditions in Texas make up approximately 26 percent of the state's total area.
- On July 30th, a total of 14 tornadoes were reported in a region that included western Tennessee, eastern Arkansas and northern Mississippi. In Arkansas, a tornado near Tichnor caused damage to a hunting club, while in Harrisburg, AR, a tornado caused damage to grain binds and a farm house. In Crumrod, AR, some damage was reported to a building there, some power lines and numerous trees. Near Lakeland, TN, a tornado caused damage to a car dealership and restaurant. In Sumner County, TN, a tornado led to the damage of several buildings. According to WKRN news, the tornado destroyed hundreds of trees in the Westmoreland area and left thousands without power. Three tornadoes touched down in Henderson County, TN, with similar damage reports. Fortunately, there were no reports of injuries associated with any of these twisters.
- For more information, please go to the Southern Regional Climate Center Home Page.
- Western Region: (Information provided by the Western Regional Climate Center)
- Except for eastern Montana, Wyoming, eastern Colorado and parts of coastal California, temperatures throughout the West were above normal. Locations in the Northwest and Southwest recorded their all time warmest July or month. Portland, OR, recorded their hottest day on record on the 28th with a daily average temperature of 90°F (32°C). The 29th followed with the second hottest day on record with an 89°F (31.7°C) average. It was Portland's second warmest July on record. Seattle-Tacoma Airport had their warmest July ever and a new all-time record maximum temperature was set on the 29th with 103°F (39.5°C). In Death Valley a new monthly average maximum temperature was set at 121.3°F (49.6°C). Twenty-two days in Death Valley reached 120°F (48.9°C) or higher which beat the old record of 19 days. In Arizona both Phoenix (98.3°F / 36.8°C) and Yuma (97.5°F / 36.4°C) notched their warmest month of all time. Denver, CO, however, recorded their coolest July in 37 years and Casper, WY, their coolest in 16 years. Thanks to a persistent marine layer, parts of coastal California were cooler than normal with lots of gray skies. Eureka, CA, never got above 67°F (19.4°C) the entire month. On several days maximum temperatures along their north coast were at least 50°F / 27.8°C cooler than inland stations.
- Precipitation was expectedly dry in California, and in the Northwest while portions of the northern Rockies, eastern Colorado and southeast New Mexico were quite wet. It was the wettest July on record in Pueblo, CO, with 5.39 inches (136.9 mm). It was also the wettest July ever in Pocatello, ID, at 2.28 inches (57.9 mm) where records go back 70 years. Conversely, it was the third driest July on record in Seattle at 0.06 inch (1.5 mm).
- For more information, please go to the Western Regional Climate Center Home Page.
See NCDC's Monthly Extremes web-page for weather and climate records for the month of May. For additional national, regional, and statewide data and graphics from 1895-present, for May, the last 3 months or other periods, 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 Climate Monitoring Products page and the Climate at a Glance page as they become available.