May gets underway !

 

A spring day at Lake Needwood, Derwood, Maryland

May completes DC's transition from winter to spring as the final month of "meteorological" spring.  It often feels like summer by the end of the month.

Average daily temperatures in May warm appreciably in the nation’s capital. Daily average temperatures range from a high/low of 73°/54° on May 1 to 80°/63° by the end of the month. DC’s hottest May temperature on record of 99° occurred on May 31, 1991. Meanwhile, DC’s coldest May temperature of 33° occurred long ago on May 11, 1906. 

DC’s May weather can be quite streaky. For example, four of DC’s 10 warmest May’s have occurred since 2012. By comparison, three of the last four May’s have been cooler than average, following DC’s very warm May’s in 2018 and 2019.  That's similar to last month that finished as DC's ninth warmest April on record and fifth April of the Top 10 to occur since 2010.

May is DC’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 2008 illustrated. That was DC’s third wettest May with 10.66” of rain and an incredible total of five days each with an inch or more of rain. On the other hand, three of the last four May's have been drier than average in Washington, D.C.

May is frequently an active severe weather month in the DC Metro Area.  Looking at DC’s May climate records, one can see that on several dates a trace of snowfall (enough to accumulate, but not enough to measure) has occurred.  Except it wasn’t actually snow, but hail.  For example, on May 2, 2016, a severe weather outbreak produced a lot of hail in the DC 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. The nation’s capital has averaged between one and two May days with highs in the 90s over the last 30 years, according to data from NOAA. DC residents can also expect to see a high of at least 95° roughly once every four to five years, with the last such occurrence being a high of 96° on May 31, 2022. 

NOAA’s Climate Prediction Center expects May 2024 to feature above average temperatures and rainfall in the nation’s capital.