Washington D.C. · September
Run in the morning.
Comfortable average high of 80°F, dipping to 63°F at night. Humidity rises with the sun — morning runs catch the driest, coolest window.
Avg high / low
80° / 63°F
Humidity
73%
Rain days
14/mo
Wind
9 mph
What September feels like in Washington D.C.
Sunrise
06:50
Mid-month average
Sunset
19:15
Mid-month average
Time-of-day breakdown
Morning
Coolest, driest air of the day. The window before sunrise is the most reliable comfortable hour.
Midday
Mild but UV and traffic peak. Workable if you don't mind shifting your pace.
Evening
Warm and runnable. Crowded routes but the air's typically calm.
What to wear running in Washington D.C. in September
The kit for September in Washington D.C.: shorts and a short-sleeve are the standard kit, a water-resistant cap or jacket on standby.
September vs the surrounding months
vs August
-6° avg high
-3 rain days
Washington D.C. in August →
September
80°F avg high
14 rain days
Best: morning
vs October
+11° avg high
+1 rain days
Washington D.C. in October →
Frequently Asked Questions
What is the best time of day to run in Washington D.C. in September?+
Morning. Humidity rises with the sun — morning runs catch the driest, coolest window.
What's the average temperature in Washington D.C. in September?+
Average high 80°F, average low 63°F.
How does September compare to surrounding months in Washington D.C.?+
Compared to August (avg high 85°F), September is cooler. Compared to October (avg high 69°F), September is warmer.
Does it rain often in Washington D.C. in September?+
Expect about 14 measurable rain days in September, on average.