May's Wild Weather in the Nation's Capital

 

April 2022 finished as a cooler and wetter than average month in the Nation’s Capital.  Not since 2019 have Washingtonians actually had a warmer than average April.  The third and final month of “meteorological” spring, temperatures will warm considerably during the month.

Daily average temperatures in the Nation’s Capital range from a high/low of 73°/54° on May 1 to 80°/63° by the end of the month.  D.C.’s hottest May temperature on record of 99° occurred on May 31, 1991.  Meanwhile, D.C.’s coldest May temperature of 33° occurred long ago on May 11, 1906.  D.C.’s May weather can also be quite streaky.  For example, while 11 of the last 20 May’s have been cooler than average, four of D.C.’s 10 warmest May’s have occurred since 2004.  By comparison, the last two May’s have each been cooler than average in the Nation’s Capital, following D.C.’s very warm May’s in 2018 and 2019. 

May is D.C.’s third wettest month of the year according to NOAA, with an average monthly rainfall total of 3.94”.  Rain can accumulate quickly in the Nation’s Capital this time of year as May 2018 illustrated.  It got off to a dry start with no measurable rainfall during the first 11 days of the month.  However, May 2018 finished as D.C.’s fourth wettest on record with a total of 8.73” of rain.  Nearly 70% of the monthly rainfall total occurred on just four days that each had over an inch of rain.  Despite the frequent rainfall during the second half of May 2018, all but there days of the month were warmer than average.

May is an active severe weather month in the D.C. Metro Area.  Looking at D.C.’s May climate records, one can see that on several dates a trace (enough to accumulate, but not enough to measure) of snowfall has occurred.  That wasn’t actually snow, but hail.  For example, on May 2, 2016 a severe weather outbreak produced a lot of hail in the D.C. Metro Area.  Small accumulations of hail were reported in spots such as at National Airport where a “trace” of frozen precipitation was observed.

Although summer doesn’t officially arrive until June, May often features summer-like heat.  D.C. has averaged between 1 and 2 days of temperatures in the 90s during the month of May over the last 30 years.  While no triple-digit May heat has been observed in the Nation’s Capital, D.C. residents can expect to see a high of at least 95° roughly once every 5 years.  NOAA’s Climate Prediction Center expects May 2022 to be warmer than average with near average rainfall in the D.C. Metro Area.