Offsetting Weather Patterns

Meteorological fall is coming to an end on this final day of November.  This month will finish with near average temperatures in the Nation’s Capital, but with roughly a third less rainfall than average.  According to NOAA, this is the eighth consecutive drier than average November in Washington, D.C.

The warmest temperature this month was 78° on November 3.  Although not record setting, 78° is DC’s average high temperature on September 19.  To put the 78° in further perspective, one can look at the past two Novembers.  DC’s warmest temperatures in November 2015 and 2016 were 80° (11-6-2015) and 83° (11-3-2016), respectively, so having similar warmth this November is consistent with recent history.  

This month’s coldest temperature was 26° on November 11, which tied the record low for the date.  It was DC’s first instance of record cold during the month of November since November 9, 1976 (also 26°).  The high temperature on November 11 was only 39° and that made it the coldest November day in Washington, D.C. since November 25, 2013 (38°/24°).

However, that frigid day was the outlier this month.  November 2017 has featured a total of four days with high temperatures in the 70s, 10 days in the 60s, 11 days in the 50s, 3 in the 40s and only one day in the 30s.  Ironically, November’s average temperature (combining daily high and low temperatures) will finish remarkably close to average.  Through November 29, DC’s average temperature (measured at National Airport) is spot on average at 49.8°.  In contrast, 13 of the last 20 November’s have been warmer than average in Washington, D.C., including the last two.

Only 1.99” of rain fell this month, compared to the monthly average of 3.17”.  The bulk of that occurred on November 7 (1.07”), which was DC’s largest daily November rainfall total since November 26, 2013 (1.46”).  The DC Metro Area has had a dry fall (since September 1) which was more than 4.7” below average.  However, July and August were so wet that DC’s rainfall deficit since January 1 is only 1.49” (through November 29).  In fact, 14 of the last 20 November’s have been drier than average in Washington, D.C., including the last eight.