How Hot Can June Get?

 

Although summer officially gets underway in June, this month isn’t usually as hot in the Nation’s Capital as it is in July or August.  Nevertheless, there have been some impressive heat waves and extreme heat in the D.C. Metro Area during the month of June.  According to NOAA, June is officially D.C.’s third warmest month of the year. 

The last 10 to 15 years have featured some especially warm and wet June weather in the Nation’s Capital.  Five of D.C’s warmest and three of D.C.’s wettest June’s have occurred just since 2006.  Consequently, there were some noticeable changes when NOAA updated its climate averages last spring (as it does every decade), to reflect the 30-year period of 1991-2020. 

Before last year when NOAA’s climate average reflected the period of 1981-2010, Washington, D.C.’s daily average high/low temperatures ranged from 80°/62° on June 1 to 88°/70° on June 30.  Now since the 30-year period has been updated, with the 2010’s replacing the 1980s, D.C.’s average June temperatures range from 81°/63° on June 1 to 89°/71° on June 30.  That may not sound like a lot but such changes over a decade are important.  Washington, D.C. also averaged 3.78” of June rainfall from 1981-2010, but now averages 4.20” for a roughly 10% increase. 

Washington, D.C. has averaged between seven and eight June days in the 90s dating back to the early 1990s.  Of those days, between one and two featured highs of at least 95°.  D.C. residents have also experienced triple-digit heat roughly once every five years over the last 30 years.  More often than not those rainier than average June’s have also been cooler than average (e.g. 1972, 2003 and 2006).  However, June 2015 was an exception that ranks as D.C.’s second rainiest and sixth warmest.

Longtime Washingtonians may recall that June was an exceptionally hot month in three consecutive years through 2012.  Memorable heat waves occurred in all three June’s (2010 – 2012) and included triple-digit heat.  However, prior to June 2010 no triple-digit June heat had occurred in the Nation’s Capital since 1997.  And none has occurred in nearly a decade when D.C.’s hottest June temperature of 104° occurred on June 29, 2012.  That helps illustrate how streaky June weather can be in Washington, D.C. 

D.C.’s 10 Wettest June’s at Reagan National Airport (DCA: Source - National Weather Service)

1.  14.02”  (2006)
2.  11.94”  (2015)
3.  11.53”  (1972)
4.  10.94”  (1900)
5.  9.97”  (2013)
6.  8.55”  (1883)
7.  7.87”  (2003)
8.  7.53”  (1916)
9.  7.41”  (1929)
10.  7.40”  (1968)

Average: 4.20”

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D.C.’s 10 Warmest June’s (DCA)

1.  80.6°  (2010)
2.  79.4°  (1994)
3.  79.2°  (1943)
4.  78.8°  (2011)
5.  78.7°  (1981)
6.  78.1°  (2015)
7.  77.9°  (2008)
8.  77.6°  (1976)
9.  77.4°  (1925)
10.  77.3°  (2017)

Average: 76.3°