Summer Heat in Washington, D.C.

Although Washington, D.C. can experience torrid heat in June, it isn’t as common as in other parts of the country.  There have been good examples of both hot and dry weather as well as just delightful weather during the month of June in the Nation’s Capital – including some of the coolest June weather in years earlier this month.

Triple digit heat is rarity in the Nation’s Capital only occurring every few years.  It occurred most recently during the very hot summer of 2012.  In fact, Washington, D.C.’s hottest June temperature on record of 104 degrees occurred on June 29, 2012.  That was the last time it was 100 degrees in June in the Nation’s Capital.  Prior to 2010, there was no triple digit heat during the month of June in Washington, D.C. since 1997.

It’s also interesting to note that seven of the ten June’s from 1997 through 2006 were cooler than average in the Nation’s Capital.  Meanwhile, eight of the following nine June’s through 2015 (with the exception of 2009) were warmer than average according to National Weather Service data.  That shows how streaky the weather can be.  On June 9, 2016, Washington, D.C. had their coolest June temperatures since 2006, when it was 53 degrees at National Airport and 47 degrees at Dulles Airport.

Washington, D.C. averages 36 days per year with temperatures at or above 90 degrees.  The record for most 90-degree days is 67 that occurred twice in 1980 and in 2010.  The fewest number of 90-degree days in a given year is 7 – that last occurred in 1905.  Washingtonians had their first 90-degree heat of 2016 on June 11, when it was 96 degrees at National Airport.  The last time the first day of 90-degree heat in the Nation’s Capital didn’t come until June was in 2003.  Prior to June 11, the last time it was at least 90 degrees in Washington, D.C. was on September 9, 2015. 

Longtime Washingtonians won’t mind a late start to summer since they’ll remember June 1994 for its stretch of 14-consecutive days with temperatures of 90 degrees or hotter.  More recently, June 2010 was the warmest June on record in the Nation’s Capital.  For those of you who thought 96 degrees was too hot this past Saturday, than I should point out residents of Phoenix, Arizona, have excessive heat warnings in effect starting on Sunday and continuing into next week.  That’s because Phoenix temperatures could approach record levels near 120 degrees.  Meteorological summer began June 1 and runs through August 31.