Record US May temps
© NOAA/NCEI
May 2018 was the hottest of any May in 124 years of recording keeping for the continental United States, eclipsing the extreme heat of that month in the 1930s during the Dust Bowl era.

The average temperature for the Lower 48 states last month was 65.41 degrees Fahrenheit, 5.21 degrees Fahrenheit above the 1901-2000 average, according to the state of the climate report released by NOAA on Wednesday.

That knocked out May 1934 for the warmest May on record. Rounding out the top five warmest Mays are 1936, 2012 and 2000.

Eight of the 12 calendar months have now notched warmth records since 1998: January (2006), March (2012), April (2006), May (2018), June (2016), September (1998), November (1999) and December (2015).

Last month, Arkansas, Illinois, Indiana, Kentucky, Missouri, Ohio, Oklahoma and Virginia broke state warmth records. Another eight states from Washington to Rhode Island had their second-warmest Mays.

All told, May 2018 ranked among the top 10 warmest on record for 40 of the Lower 48 states. No state was colder than average in May.

More than 8,590 warm temperature records were broken or tied last month at individual weather stations across the U.S., NOAA said. The number of cold temperature records broken or tied in May pales in comparison at just over 450.

Last month was a reversal from April 2018, which ranked as the coldest in more than two decades. The waves of cold air that kept the central and eastern states shivering in April gave way to record or near-record warmth in some of the same areas.


Comment: The winter that wouldn't quit: Cold continues, sets records in US


Oklahoma, Missouri and Illinois had notable temperature swings from April to May 2018. The second coldest April on record in those states was followed by record warmth in May.

Last month also brought record or near record wet conditions in parts of the Southeast and mid-Atlantic states.

Florida and Maryland had their wettest Mays dating to 1895. Georgia, Delaware, North Carolina, South Carolina and Virginia had their top 10 wettest.

When examining both precipitation and temperatures, the mid-Atlantic region arguably had the most extreme May.

In addition to being record wet in May, Maryland had its third-warmest May. Virginia's record warmth was accompanied by its sixth-wettest May. North Carolina had its third-warmest and third-wettest May.

A global perspective of temperatures compared to average in May shows that the U.S. was not alone when it comes to above-average warmth.

May 2018 ranked as the third-warmest May on record across the world's land and ocean surfaces, according to the Copernicus Climate Change Service, operated by the European Centre for Medium-range Weather Forecasts.