Record Heat Coincides with October’s Arrival

Fall is a great time of the year in the DC Metro Area

September 2019 finished as DC’s third warmest on record with an average monthly temperature of 76.5° (combining daily high and low temperatures).  Five of DC’s 10 warmest September’s have now occurred since 2005.  Last month was also poised to finish tied with September 2005 for DC’s driest.  However, 0.14” of rain on September 30 caused last month to finish as DC’s fourth driest with 0.25”.  Monday’s rainfall also ended a 17-day stretch without measurable rainfall in the Nation’s Capital.  Last month was DC’s driest overall month since March 2006 (0.05”).

October has picked up where last month left off with record heat on tap today with highs in the low to mid 90s for the DC Metro Area.  There’s also a chance DC could set a new record high today for the entire month of October.  DC’s hottest October temperature on record is 96° and occurred way back on October 5, 1941.  Although Washingtonians experienced one October day with 90° heat last year, there have been only five Octobers with such unusual heat in the last 25 years.  That includes October 2007 when DC had a highly unusual heat wave with three days of 90° heat from October 7 – 9.  

Average high and low temperatures fall throughout the month of October from 74°/56° on October 1 to 64°/46° on October 31.  DC’s coldest October temperature of 26° occurred twice, most recently on October 31, 1917.  There has been a nearly even split with 11 of the last 20 Octobers that were warmer than average in Washington, D.C.

The Nation’s Capital averages 3.4” of rain during the month of October.  Although the last four October’s have been drier than average in Washington, D.C., there has been an even split with 10 of the last 20 Octobers having been wetter than average.  While last month fell just short of tying DC’s 2005 record for driest September, many comparisons have been made since both Septembers were significantly warmer and drier than average.  It’s worth pointing out that October 2005 featured a major shift in the opposite direction from the previous month and finished as DC’s wettest on record.

NOAA’s outlook for October 2019 doesn’t call for a significant deviation from normal rainfall in the Nation’s Capital.  It shows an equal chance for above or below normal rainfall with an elevated potential for below average rainfall in parts of southern Maryland and Virginia.  Significantly warmer than average temperatures are expected for the month.  That doesn’t mean there won’t be some chilly, fall-like weather at times this month; but October as a whole is expected to finish as a warmer than average month in the Nation’s Capital. 

October 2 Record Highs (Source: NOAA)

National Airport, Washington, D.C. (DCA): 89° (1986, 1881)
Dulles Airport, Sterling, Virginia (IAD): 89° (1986)
BWI Airport, Baltimore, MD: 89° (1986)

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All-Time October Record Highs (Source: NOAA)

DCA: 96° (October 5, 1941)
IAD: 94° (October 9, 2007)
BWI: 97° (October 5, 1941)