Under the influence of an unusually deep pool of cool air for late July, temperatures across the D.C. and Baltimore areas plummeted into the 50s and even the 40s in a few spots this morning.

The low temperatures were record-setting at both Dulles and BWI airports.

The mercury at Dulles dropped to an astonishingly low 48 degrees, shattering the record of 51 from 1981. Records at Dulles have been kept since 1963.

It’s the third record low at Dulles this month (the temperature fell to 52 before midnight yesterday, below the previous July 29 record of 53 from 1978; in addition, Dulles tied a record low on July 17 of 55, from 1976).  CWG’s Matt Rogers notes this is  the first time in the 1990s-2000s that the airport has experienced three record lows in the same July.

CWG’s Ian Livingston adds that the low of 48 at Dulles this morning is the coolest July morning there since July 12, 2002 when it hit 47.  In other words, it was the coolest July morning in over 10 years.

At BWI Airport, the temperature fell to 55 degrees, edging below the previous record low of 56 from 1997. This is the fifth record low matched or exceeded at BWI this month (see yesterday’s post: Baltimore–that is BWI Airport–logs 4th record low this July). Records have been kept at BWI since 1950, part of a longer dataset for Baltimore which extends back to 1871. Prior to BWI, weather records for Baltimore were maintained at the U.S. Custom House downtown.

Reagan National Airport, D.C.’s official observation location, dipped to 60 degrees – four degrees shy of the record of 56 set in 1914 when D.C.’s observing station was located at 24th and M St. in the District. D.C.’s weather records date back to 1871.