A wet September and October is ideal for bright fall colors. On the contrary, a drier than average late summer and early fall accelerates the leaf-changing process and the leaves tend to fall before the best color can be reached.
In Washington, while the year has been wetter than average, September has been mostly dry. Rainfall deficits are 2.0 to 2.50 inches inside the Capital Beltway. Central Virginia is also a bit drier than average with rainfall deficits around 2.50 inches as well. The Interstate 81 is in better shape with Hagerstown, Md., and Martinsburg, W.Va., in a 0.80 to 1.10 inch deficit.
Therefore, the dry trend does not bode well for an exquisite outbreak of luscious colors. Looking ahead, the upcoming pattern doesn’t favor rain until the end of the month.
What else helps to create deep oranges and yellows, etc., in the fall foliage? Warm, sunny days followed by crisp, cool nights with temperatures above freezing. Therefore, high temperatures in the 60s and 70s with lows in the middle 30s to around 50 degrees.
The sharp temperature changes keeps sugars from reaching the leaf’s root system so the sugars are converted into pigments that produce the brilliant colors.
The upcoming pattern, while dry, favors a nice swing in temperatures with highs in the 70s and lows in the 50s. This trend is also right on par with climatological averages in the nation’s capital. A biting frost or early hard freeze is not on the near horizon in the western suburbs, which will help bring out the wonderful colors.
Frequent rain and wind events in the fall will bring the leaves down before they reach peak color as well.
So, while the month will likely end drier than average, the soggy summer will hopefully pull through and the favorable temperature trend could be the icing on the cake to a picturesque fall!
Here’s a look at when fall colors typically peak in the region; the colors first appear in the Alleghenies by early October and then the foliage season migrates into the District by Halloween. The eastern shore is the last to see the best colors; here it’s usually a few weeks prior to Thanksgiving.
Want to know the full process of how the leaves change color? Check out this detailed fall foliage blog by Alex Liggitt on the transformation the leaves go through to become vibrant in the fall.