Cool, Wet and un-May like

NOAA hints at a potential warm up by late-May

Many Washingtonians will recall that May 2015 was the warmest on record in the Nation’s Capital.  It was also the fifth time in the previous six years that May had been drier than average.  However, temperatures so far this month have been more than four degrees cooler than average.  Also, there has already been more rain at National Airport (4.01”) than is average for all of May (3.99”).

Four days this month have had high temperatures only in the 50s for the first time since May 2005.  That’s more than halfway to the record of seven for most May days below 60 degrees in Washington, D.C.  There hasn’t been any 80-degree warmth so far this month and none is expected until at least next week.  Daily average high temperatures are in the 70s for most of May, so 80-degree warmth is quite common in May.  In fact, 90-degree heat has occurred in Washington, D.C. during 15 of the last 23 May’s according to the National Weather Service.

Since this cooler and wetter than average weather began late last month, people have compared our weather to that of Seattle, Washington.  While Seattle’s reputation for sustained periods of rainy and cool weather is well known, it has actually been significantly warmer and drier than average there this spring.  Ironically, while Seattle averages more days with measureable rain in a given year than Washington, D.C. (152 to 115 days), Washington, D.C. averages more annual rainfall (39.74” to 36.15”), according to NOAA. 

This month’s cool weather and record streak of 15 consecutive days with measureable rain (that continued through May 11) has been inhospitable for outdoor activities.  Although there have been only three dry days so far this month, it’s too early to call this one of the coolest and wettest Mays on record.

As this May’s rainy pattern continues, you will hear more comparisons to the record-setting May of 2003 when rain fell on 24 days.  Overall, Washington, D.C.’s wettest May on record occurred in both 1953 and 1889 when 10.69” of rain fell.  Our coolest May on record occurred twice – most recently in 1907 – when the average temperature (combining daily high and low temperatures) was 59.2 degrees.