Austin · September
Run in the pre-dawn.
Average high is 90°F with a 73°F overnight low. Humid heat punishes mid-morning — get out before sunrise for the only truly comfortable window.
Avg high / low
90° / 73°F
Humidity
67%
Rain days
13/mo
Wind
10 mph
What September feels like in Austin
Sunrise
07:15
Mid-month average
Sunset
19:35
Mid-month average
Time-of-day breakdown
Morning
Steady cool air, low wind, and good light. The standard runner window in most months.
Midday
Heat peaks here. Skip unless you've got shade and pace tolerance.
Evening
Cools off after sunset but still warm. Good for easy efforts; avoid hard intervals if you're chasing pace.
What to wear running in Austin in September
The kit for September in Austin: light, breathable, and moisture-wicking — singlet or short-sleeve only, a water-resistant cap or jacket on standby.
September vs the surrounding months
vs August
-6° avg high
+1 rain days
Austin in August →
September
90°F avg high
13 rain days
Best: pre-dawn
vs October
+8° avg high
+2 rain days
Austin in October →
Frequently Asked Questions
What is the best time of day to run in Austin in September?+
Pre-dawn. Humid heat punishes mid-morning — get out before sunrise for the only truly comfortable window.
What's the average temperature in Austin in September?+
Average high 90°F, average low 73°F.
How does September compare to surrounding months in Austin?+
Compared to August (avg high 96°F), September is cooler. Compared to October (avg high 81°F), September is warmer.
Does it rain often in Austin in September?+
Expect about 13 measurable rain days in September, on average.