U.S. National Overview
May 2006

May:

• May temperatures were above normal for the contiguous United States. Nationally, it was the fifth warmest May in the 1895-2006 record. The southwest, from Texas to California was much above average. Near to below normal temperatures covered much of the U.S. east of the Mississippi, except the Northeast, which experienced above normal temperatures for the month. For information on temperature records during the month, please go to NCDC's Extremes page.
  
  
• Precipitation was below average for the contiguous U.S. with dryness occurring primarily in the West-Central Plains and Rocky Mountain regions, while the northern Midwest and the Northeast experienced above to much above normal precipitation in May. Record rainfall resulted in extensive flooding in New England between 10-15 May. Significant drought continued in the Southern Plains and Desert Southwest, with exceptional drought persisting in southernmost Texas. For more information on drought during May, please visit the U.S. Drought page.
  
  
• Tornado producing thunderstorms claimed three lives on 9 May in Collin Co., TX, just northeast of Dallas. Twenty-six homes were damaged and 10 injuries also were reported.
  
  
• Tropical Storm Aletta led off the Eastern North Pacific 2006 Tropical Cyclone Season. Aletta formed on 27 May and dissipated on the 30th, reaching maximum sustained winds of 40 kts (46 mph or 74 km h^-1). For statistics on the Eastern North Pacific storm season, please see NCDC's 2006 Northeast Pacific Tropical Cyclone page. The Atlantic season begins on 01 June.

• Indices used to determine the state of ENSO indicate neutral conditions that are expected to persist through the next several months. Sea Surface Temperatures were near average across the eastern equatorial Pacific during May. To see the latest NOAA advisory and typical impacts of a La Niña or El Niño episode for the U.S., go to NOAA's Climate Prediction Center. For an in-depth analysis of the current conditions see NCDC's ENSO Monitoring page.

• May 2006 was the fifth warmest May in the 1895 to present record. The preliminary nationally averaged temperature was 63.7°F (17.6°C), which was 2.7°F (1.5°C) above the 1901-2000 (20th century) May mean.
  
  
• May 2006 had below average precipitation, nationally, ranking 17th driest in the 1895-2006 record. An average 2.33 inches (59 mm) fell over the contiguous U.S. in May, 0.54 inches (14 mm) below the 1901-2000 average for the month.
  
  
• Boreal spring (Mar-May) temperature was much above average and ranked as the 4th warmest such period in the 1895-to-present record. The preliminary nationally averaged temperature for February-April was 54.7°F (12.6°C) which was 2.9°F (1.6°C) above the 1901-2000 spring mean.
  
  
• March-May had below average precipitation, ranking as the 31st driest spring in the last 112 years. The 7.11 inches (181 mm) average March-May precipitation for the nation was 0.6 inches (15 mm) below the 1901-2000 average for the 3-month period.
  
  
• The June 2005 - May 2006 temperature was also much above average and, based upon preliminary data, ranked as the warmest such period in the 1895-2006 record. The preliminary nationally averaged temperature was 55.2°F (12.9°C) which was 2.4°F (1.3°C) above the 20th century mean for this period.
  
  
• Precipitation was near average for May-April, ranking 41st driest for the last 12 months based on a record of 111 such periods. Nationally averaged total precipitation was 28.68 inches (728 mm), or 0.47 inch (12 mm) below the 1901-2000 average for this 12-month period.

• May 2006 temperatures ranked much above normal for the Southwestern tier and below normal for 4 Eastern states. The remainder of the west and northeastern U.S. was above normal, while the remainder of the eastern U.S. was near normal.
  
  
• April was much drier than average for Nebraska and Iowa and much wetter than average for Michigan and for much of New England.
  
  
• Boreal spring (March - May) temperatures were above to much-above average for all contiguous US states, except California, which was near average. Four states in the Southern Plains experienced record warmth for this period.
  
  
• March - May was drier to much-drier than average for the Southeast and Mid-Atlantic regions, as well as the eastern Rocky Mountain region and Maine. Wetter-than-average spring conditions previaled in parts of New England, the northern Midwest, and the western Rocky Mountains. California had much-above normal precipitation.
  
  
• June 2005 - May 2006 was warmer or much warmer than average for all of the contiguous U.S., with record warmth for 10 states.
  
  
• The last 12 months had a mixed precipitation pattern across the country. There were 7 states that were much wetter than average, including record wettness for New Hampshire, and there were 5 states across the southern US that were much drier than average.

  
  See NCDC's Monthly Extremes web-page for weather and climate records for the month of May.