Jacksonville · September
Run in the morning.
Comfortable average high of 85°F, dipping to 73°F at night. Humidity averages 83% — the limiting factor on most runs. Expect 21 rain days — plan around the radar. Humidity rises with the sun — morning runs catch the driest, coolest window.
Avg high / low
85° / 73°F
Humidity
83%
Rain days
21/mo
Wind
11 mph
What September feels like in Jacksonville
Sunrise
07:11
Mid-month average
Sunset
19:31
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 Jacksonville in September
The kit for September in Jacksonville: shorts and a short-sleeve are the standard kit, a water-resistant cap or jacket on standby.
September vs the surrounding months
vs August
-3° avg high
-6 rain days
Jacksonville in August →
September
85°F avg high
21 rain days
Best: morning
vs October
+5° avg high
+8 rain days
Jacksonville in October →
Frequently Asked Questions
What is the best time of day to run in Jacksonville in September?+
Morning. Humidity rises with the sun — morning runs catch the driest, coolest window.
What's the average temperature in Jacksonville in September?+
Average high 85°F, average low 73°F.
How does September compare to surrounding months in Jacksonville?+
Compared to August (avg high 88°F), September is cooler. Compared to October (avg high 79°F), September is warmer.
Does it rain often in Jacksonville in September?+
Expect about 21 measurable rain days in September, on average.