The Arrival of Meteorological Summer

What can DC area residents expect now that meteorological summer has arrived?  Some of the hottest weather in the Mid-Atlantic Region has occurred in June.  In Washington, D.C., average high and low temperatures rise from 80°/62° on June 1 to 88°/70° on June 30. 

June’s hottest recorded temperature in the Nation’s Capital is 104° which occurred relatively recently on June 28, 2012.  That was the last time Washingtonians experienced 100° heat in June.  The earliest in the season it’s been 100° in the Nation’s Capital was on June 5, 1925.  Meanwhile, DC’s coolest June temperature remains the 43° which occurred on June 2, 1897.  While weather records in Washington, D.C. date back to 1871, measurements have only been made at National Airport since it opened in 1941. So, the 104° and 43° record June temperatures were measured in different locations.

The Nation’s Capital averages 3.78” of rain in June.  Twelve of the last 20 Junes have been wetter than average.  The remnants of a tropical system occasionally bring the Mid-Atlantic Region significant rainfall in June, such as Agnes in 1972.  Severe weather can also occur during the month of June in the Mid-Atlantic Region.  One of the strongest tornadoes on record in the state of Maryland occurred in Frostburg on June 2, 1998.  Also, the infamous “derecho” occurred on June 28, 2012.

Washingtonians have had a rainfall deficit since August 2015.  Fortunately, the wetter than average month of May 2017 made up some of that deficit and eliminated the local drought conditions.  It was the first wetter and cooler than average month in Washington, D.C. since May 2016.  That’s despite DC experiencing its hottest May day in nearly six years on May 19 when it was 93°.  Last month was also the fifth wettest May on record at Dulles Airport (8.49”).

There is no correlation between a cool and wet May and what June’s weather will be like.  Washingtonians had a cooler and wetter than average May last year, but last summer was one of the hottest on record.  Also, a wetter than average June doesn’t foreshadow what the entire summer will be like.  DC’s wettest June on record (14.02”) occurred in 2006, but the rest of the summer was drier than average.  NOAA’s outlook for June is for near average temperatures in the Mid-Atlantic Region with the potential for above average precipitation.