San Francisco · September
Run in the morning.
Comfortable average high of 71°F, dipping to 58°F at night. Humidity averages 77% — the limiting factor on most runs. Dry month — only 2 measurable rain days on average. Humidity rises with the sun — morning runs catch the driest, coolest window.
Avg high / low
71° / 58°F
Humidity
77%
Rain days
2/mo
Wind
15 mph
What September feels like in San Francisco
Sunrise
06:52
Mid-month average
Sunset
19:16
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 Francisco in September
The kit for September in San Francisco: shorts and a short-sleeve are the standard kit, a wind-blocking layer for exposed routes.
September vs the surrounding months
vs August
+2° avg high
+2 rain days
San Francisco in August →
September
71°F avg high
2 rain days
Best: morning
vs October
+2° avg high
-2 rain days
San Francisco in October →
Frequently Asked Questions
What is the best time of day to run in San Francisco in September?+
Morning. Humidity rises with the sun — morning runs catch the driest, coolest window.
What's the average temperature in San Francisco in September?+
Average high 71°F, average low 58°F.
How does September compare to surrounding months in San Francisco?+
Compared to August (avg high 68°F), September is warmer. Compared to October (avg high 69°F), September is warmer.
Does it rain often in San Francisco in September?+
Expect about 2 measurable rain days in September, on average.