Feeling Like Fall

Temperature Outlook for the End of October 2018  (Source: NOAA)

This October got off to the warmest start on record in the Nation’s Capital.  However, while this week will feature plenty of sunshine, temperatures will actually be cooler than average for most of the week in the DC Metro Area.  The expected high temperatures in the mid to upper 50s on Wednesday, Thursday and Friday are more characteristic of mid-November than late-October.

October 2018 has been a unique weather month so far.  High temperatures were 81° or warmer on nine of the first 11 days of the month, including DC’s first 90° temperature in five years on October 4^th.  But, high temperatures have been cooler than average on six of the nine days since October 13.  Consequently, October’s average monthly temperature (combining daily high and low temperatures) in the Nation’s Capital has dropped from 74.7° on October 13 to 66.4° today.  

With the exception of near average high temperatures today in the mid to upper 60s, temperatures will be cooler than average the rest of the week.  In fact, NOAA expects below average temperatures to continue for much of the next six to 10 days.  Nevertheless, it’s worth pointing out that four of the last five Octobers (2013 – 2017) have had monthly temperatures at least 2.9° warmer than average.

Given the warm September and warm start to October, leaves have been slow to start changing color.  However, the cooler than average temperatures and decreasing amount of daylight should hasten the fall colors.  The fall foliage doesn’t normally reach its peak until early November in the immediate DC Metro Area and there should be plenty of color by then.  

Washington, D.C. has had a total of 1.81” of rain since October 1.  Although the bulk of this week will be dry, there is an increasing potential for appreciable rainfall on Saturday due to an early-season Nor’Easter.  Any additional rainfall would put DC closer to its October average of 3.40”.  Ten of the last 20 October’s have been wetter than average, but that hides how streaky October rainfall has been in the Nation’s Capital.  Ten of the 13 Octobers from 2002 – 2014 were wetter than average, while the last three have been drier than average.

DC’s Warmest Octobers (Source: National Weather Service)

1.  67.1° - 2007
2.  65.2° - 1984
3.  64.9° - 2017
4.  64.7° - 1971
5.  64.5° - 1947
6.  64.4° - 1941
7.  63.4° - 1949
8.  63.3° - 1973
9.  63.2° - 1975, 1919
11.  63.1° - 2016
12.  63.0° - 1879
13.  62.9° - 2014, 1881
15.  62.8° - 1990
16.  62.5° - 1970

59.5° - Average