Spring was warmest on record, NOAA reports

/ Source: msnbc.com

This spring was the warmest on record across the contiguous U.S., scientists reported Thursday. On top of that, spring was 5.2 degrees warmer than average -- the largest temperature variance for any season on record.

"The fact that the U.S. has been in a warm pattern for several months is continuing to be the big story," Jake Crouch, who prepares the monthly climate reports for the National Oceanic and Atmospheric Administration, told msnbc.com.

"Two things really jump out at me" in this month's State of the Climate report, he added:

  • June 2011 through May 2012 "broke the record for warmest consecutive 12 months, which we just broke last month" with May 2011 to April 2012. Moreover, each of the last 12 months ranked in the top third of the historical distribution -- the first time that's happened in 117 years of record keeping. "If we assume that each month has an equal chance of having temperatures in the top third," Crouch said, "the odds of this happening are one in 531,441."
  • Each month of spring (March, April, May) "all ranked as top-ten warm" -- also the first time that's happened.

Overall, spring averaged 57.1 degrees -- 2 degrees above the previous record set in 1910 and 5.2 degrees above the 1901-2000 average for spring. The previous record differential was 4.2 degrees in the winter of 1999/2000.

Each of the previous three seasons were also well above average: 2.4 degrees last summer, 1.3 degrees in fall, and 3.9 degrees in winter.

"We don't have enough data yet to fully understand how the recent warm seasons will fit into the longer term trend," Crouch added, "but that is something we will continue to monitor as we move into the summer."

Other statistics highlighted by NOAA:

  • May was the second warmest on record at 64.3 degrees.
  • January-May was the warmest stretch for those months on record. The average temperature of 49.2 degrees was 5 degrees above the long-term average.
  • During the record June 2011 through May 2012 warmth (averaging 56 degrees, 0.4 degrees warmer than the previous record) every lower 48 state but one -- Washington -- saw above average temps.

It's tempting to tie the warmer temperatures to manmade emissions and climate change, but NOAA emphasizes in its reports and statements that weather is influenced by other, natural factors as well. Instead, it notes that the warm pattern is indicative of what one would expect with climate change.