Denver · September
Run in the morning.
Comfortable average high of 81°F, dipping to 52°F at night. Comfortable conditions all day, but morning consistently delivers the best combination of cool air and clear skies.
Avg high / low
81° / 52°F
Humidity
45%
Rain days
8/mo
Wind
10 mph
What September feels like in Denver
Sunrise
06:42
Mid-month average
Sunset
19:07
Mid-month average
Time-of-day breakdown
Morning
Steady cool air, low wind, and good light. The standard runner window in most months.
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 Denver in September
The kit for September in Denver: shorts and a short-sleeve are the standard kit.
September vs the surrounding months
vs August
-5° avg high
-3 rain days
Denver in August →
September
81°F avg high
8 rain days
Best: morning
vs October
+16° avg high
+1 rain days
Denver in October →
Frequently Asked Questions
What is the best time of day to run in Denver in September?+
Morning. Comfortable conditions all day, but morning consistently delivers the best combination of cool air and clear skies.
What's the average temperature in Denver in September?+
Average high 81°F, average low 52°F.
How does September compare to surrounding months in Denver?+
Compared to August (avg high 86°F), September is cooler. Compared to October (avg high 66°F), September is warmer.
Does it rain often in Denver in September?+
Expect about 8 measurable rain days in September, on average.