Rare April Weather Events

April 2018 will be remembered as a cooler and wetter than average month.  That’s good, however, since the DC Metro Area got some beneficial rainfall.  Washingtonians had 3.59” of rain, making this month D.C.’s second wetter than average month of 2018.  Through April 29, D.C.’s average monthly temperature (combining daily high and low temperatures) is 54.8° or 1.8° cooler than average.

The latest Drought Monitor Index shows abnormally dry conditions exist for parts of the DC Metro Area.  A small area of moderate drought conditions also exists within D.C. City limits, making April’s rainfall surplus especially timely.  This month’s 3.59” ranks more than half an inch above D.C.’s April average of 3.06”.  That’s helped reduce D.C.’s rainfall deficit to 0.63” since January 1.  Prior to this month, the last time Washington, D.C. had an April that was both cooler and wetter than average was in 2007.  

D.C.’s warmest temperature this month was 86° on April 13.  By comparison, the temperature fell to 34° twice on April 5 and April 8.  Above average temperatures have been relatively rare this month.  For example, high temperatures in the Nation’s Capital have been at or below average on all but 11 days since April 1. 

April has also been a windy month in the Nation’s Capital with average wind speeds reaching at least 10 mph on 19 days.  Severe weather occurred in parts of central and southern Virginia on April 15.  That coincided with the 2.01” of rain that Washington, D.C. saw on April 15-16.  That was D.C.’s largest two-day April rainfall total since 2014.

April is the second month of meteorological spring that runs from March 1 through May 31.  It is an important transitional weather month for much of North America.  With average temperatures that range from a high/low of 62°/42° on April 1 to 71°/52° on April 30, it bridges the gap between chilly March temperatures and the warmer temperatures of May.  Some of the DC Metro Area’s most significant severe weather has also occurred during the month of April from the La Plata tornado of 2002 to the severe weather outbreak of April 27-28, 2011.