San Diego · September
Run in the morning.
Comfortable average high of 78°F, dipping to 65°F at night. Humidity averages 77% — the limiting factor on most runs. Dry month — only 3 measurable rain days on average. Humidity rises with the sun — morning runs catch the driest, coolest window.
Avg high / low
78° / 65°F
Humidity
77%
Rain days
3/mo
Wind
11 mph
What September feels like in San Diego
Sunrise
06:32
Mid-month average
Sunset
18:54
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 San Diego in September
The kit for September in San Diego: shorts and a short-sleeve are the standard kit.
September vs the surrounding months
vs August
0° avg high
+2 rain days
San Diego in August →
September
78°F avg high
3 rain days
Best: morning
vs October
+2° avg high
0 rain days
San Diego in October →
Frequently Asked Questions
What is the best time of day to run in San Diego in September?+
Morning. Humidity rises with the sun — morning runs catch the driest, coolest window.
What's the average temperature in San Diego in September?+
Average high 78°F, average low 65°F.
How does September compare to surrounding months in San Diego?+
Compared to August (avg high 78°F), September is warmer. Compared to October (avg high 76°F), September is warmer.
Does it rain often in San Diego in September?+
Expect about 3 measurable rain days in September, on average.