Monthly Report Summary Information
The Monthly Report Summary Information is a synopsis of the collection of national and global summaries released each month.
National Summary Information - May 2015
See Full Report
For extended analysis of regional temperature and precipitation patterns,as well as extreme events, please see our full report that will be released on June 10th.
May was wettest month on record for contiguous US
Devastating floods end multiyear drought in Southern Plains
The May contiguous U.S. average temperature was 60.8°F, 0.6°F above the 20th century average, near the median value in the 121-year record. Much of the East Coast and Northwest were warmer than average, particularly the Northeast where four states were record warm. Below-average temperatures were observed across the central U.S. The spring (March-May) contiguous U.S average temperature was 53.2°F, 2.2°F above the 20th century average, and the 11th warmest on record.
The May precipitation total for the contiguous U.S. was 4.36 inches, 1.45 inches above average. This was the wettest May on record, and the wettest month of any month, in the 121-years of record keeping. For the spring season, the contiguous U.S. precipitation total was 9.33 inches, 1.39 inches above average, and the 11th wettest on record.
This analysis of U.S. temperature and precipitation is based on data back to January 1895, resulting in 121 years of data.
- Above-average temperatures were widespread in the East, where 15 states were much warmer than average. Connecticut, Massachusetts, New Hampshire and Rhode Island were each record warm. In the Pacific Northwest, Washington was also much warmer than average. Below-average temperatures spanned the Great Plains and Southern Rockies.
- The Alaska statewide average temperature for May was the warmest on record in 91 years of record keeping at 44.9°F, 7.1°F above average. The warmth in Alaska was widespread with several cities were record warm, including Barrow and Juneau.
- Wetter than average conditions were widespread across the central United States. Fifteen states from the Great Basin to Mississippi River had precipitation totals that were much above average. Colorado, Oklahoma, and Texas were each record wet for the month. In fact, Oklahoma and Texas each had their wettest month of any month on record with precipitation totals more than twice the long-term average.
- The heavy rains in the central U.S. were accompanied by severe weather with over 400 preliminary tornado reports, the most since April 2011. The flooding rains and severe weather resulted in dozens of fatalities and widespread property damage.
- Much of the East Coast was drier than average, despite the record high contiguous U.S. precipitation value and despite tropical storm Ana making landfall in the Carolinas early in the month. Seven states from the Southeast to New England had May precipitation totals that were much below average. No state was record dry.
- According to the June 2 U.S. Drought Monitor report, 24.6 percent of the contiguous U.S. was in drought, down from 37.4 percent at the end of April and the smallest drought footprint since February 2011. Drought conditions drastically improved across the Southern Plains. Drought improvement was also observed across the Central and Northern Plains, Upper Midwest, and the Central Rockies. Drought conditions developed and worsened across parts of the Northeast, Southeast, Northwest, and Puerto Rico. Drought conditions remained entrenched in the West.
U.S. climate highlights: spring (March-May)
- Much of the contiguous U.S. was warmer than average during spring, except the Southern Plains and the Northeast. The Southeast and West were especially warm, where 11 states were much warmer than average. Florida had its warmest spring on record, with a temperature of 74.1°F, 4.6°F above average, and 1.1°F warmer than the previous record that occurred in 2012.
- Similar to May, above-average spring precipitation was observed across the Central and Southern Plains. Six states were much wetter than average, including Texas which had its wettest spring on record with more than twice its average precipitation. Below-average precipitation was observed along both coasts; seven states were much drier than average.
- The U.S. Climate Extremes Index (USCEI) for spring was slightly below average. On the national-scale, extremes in warm maximum and minimum temperatures and days with precipitation were much above average. The USCEI is an index that tracks extremes (falling in the upper or lower 10 percent of the record) in temperature, precipitation and drought across the contiguous U.S.
U.S. climate highlights: Year-to-date (January-May)
- The year-to-date contiguous U.S. average temperature was 45.1°F, 1.8°F above the 20th century average, and the 17th warmest January-May on record.
- Much warmer than average conditions were observed from the Rockies to the West Coast and in Florida. California was record warm for January-May with a temperature 5.1°F above average and 0.1°F warmer than the previous record set just last year. Below-average temperatures for the year-to-date were observed in the Midwest and Northeast, where New York was much cooler than average. No state was record cold.
- The year-to-date contiguous U.S. precipitation total was 12.91 inches, 0.52 inch above the 20th century average, and ranked among the wettest third of the historical record.
- Above-average precipitation was observed across the Great Plains and the Southern Rockies, where five states were much wetter than average. Texas had its wettest year-to-date on record with 20.11 inches, 9.63 inches above average. Below-average precipitation was observed across the West and the Northeast. California had its fifth driest start to the year, while New York had its third driest. Six additional states in the Northeast were much drier than average.
- The USCEI for the year-to-date was 30 percent above average and the 19th highest value on record. The components that measure extremes in warm maximum and minimum temperatures and days with precipitation were much above average.
Update on 2014 Billion Dollar Weather Disasters
- Updating our January release on the number of billion dollar weather and climate events last year, in 2014, there were eight weather and climate disaster events with losses exceeding $1 billion each across the United States that cumulatively caused over $17 billion in losses. This makes 2014 similar to 2013, which had nine events and over $24 billion in losses (CPI-adjusted). Since 1980, the year 2011 had the most billion-dollar events (16) while 2005 remains the most damaging year with over $200 billion in losses (CPI-adjusted).
For extended analysis of regional temperature and precipitation patterns, as well as extreme events, please see our full report that will be released on June 10th.