How Warm has 2015 been in the Nation’s Capital?

Sunset in Ocean City, MD - a popular summer tourist spot!  (Courtesy: Lori Adams)

This year has featured one of the Mid-Atlantic Region’s warmest summers in recent memory with the highest number of 90 degree days since 2012 (officially 52 at National Airport).  Our weather pattern has taken a major shift sure to please all those who are eager for cooler, more fall-like weather.  Yesterday was a transitional day with the first measurable rainfall in the DC Metro Region in more than two weeks.  It is also important to note that all weather measurements for the Nation’s Capital are made at National Airport.

Although Washington, D.C. didn’t have any record highs this summer, the higher than average number of 90 degree days put this year in the conversation with the torrid summers of 2010 through 2012. May 2015 was the warmest on record in the Nation’s Capital, and that continued into June (DC’s sixth warmest on record).  Washingtonians have already sweat through seven days of 90 degree heat this month, which has produced record heat on both the East and West Coasts.  New York City’s Central Park broke a record high on Tuesday (when it was 97 degrees) that dated back to 1919.

The summer of 2010 included the warmest June on record, with the first triple digit heat observed in the Nation’s Capital since 2007.  2010 also tied the record (from 1980) for most 90 degree days in a year with 67.  Washington, D.C. averages 36 days of 90 degree heat in a given year.

The summer of 2011 was similarly hot in the Nation’s Capital, with a monthly record 25 days of 90 degree heat in July.  That was the hottest month on record in Washington, D.C. with an average temperature (including both daily high and low temperatures) of 84.5 degrees.  All told, there were 50 days of 90 degree heat in the Nation’s Capital in 2011.  July 2012 saw seven days of triple digit heat in the Nation’s Capital – including the last triple digit heat to occur in the Nation’s Capital.  There were 53 days of 90 degree heat in Washington, D.C., in 2012, 35 days in 2013 and only 24 days last year.

It’s interesting to note that during this summer in the DC Metro Region, the suburbs have been much cooler than downtown.  For example, Dulles Airport has had only 21 days at or above 90 degrees this year, while BWI Airport has observed only 26 such days.  It’s remarkable to consider that National Airport has seen more 90 degree days this year than Dulles and BWI Airports combined. Some of that could be contributed to the urban heat island effect, while some will hold the last few months of data at National Airport with a degree of skepticism due to the faulty sensor that was recently replaced.

Going forward residents and tourists alike can look forward to more autumn-like weather. The fall is a beautiful time of year in the Mid-Atlantic Region and temperatures are looking quite comfortable during the next seven days.