Chicago · September
Run in the morning.
Comfortable average high of 74°F, dipping to 61°F at night. Humidity rises with the sun — morning runs catch the driest, coolest window.
Avg high / low
74° / 61°F
Humidity
75%
Rain days
13/mo
Wind
14 mph
What September feels like in Chicago
Sunrise
06:31
Mid-month average
Sunset
18:59
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 Chicago in September
The kit for September in Chicago: shorts and a short-sleeve are the standard kit, a water-resistant cap or jacket on standby.
September vs the surrounding months
vs August
-5° avg high
-4 rain days
Chicago in August →
September
74°F avg high
13 rain days
Best: morning
vs October
+13° avg high
-2 rain days
Chicago in October →
Frequently Asked Questions
What is the best time of day to run in Chicago in September?+
Morning. Humidity rises with the sun — morning runs catch the driest, coolest window.
What's the average temperature in Chicago in September?+
Average high 74°F, average low 61°F.
How does September compare to surrounding months in Chicago?+
Compared to August (avg high 79°F), September is cooler. Compared to October (avg high 61°F), September is warmer.
Does it rain often in Chicago in September?+
Expect about 13 measurable rain days in September, on average.