Avg High
San Francisco in September
Verdict
In San Francisco, September has a distinct autumn feel. As the season moves along, the weather is warming up. You can usually expect a mild month that feels reliable day to day. Breezes can be part of the character, especially in exposed spots.
Well suited to visitors who prefer a steady feel over dramatic shifts. Lookouts and coastal walks can feel sharper when the wind is up.
Avg Low
Rain
Daylight
12h
What to expect
- Daytime feel - Summer-like warmth with evenings that feel distinctly cooler. Overall it feels close to what you’d expect.
- Rain pattern - Mostly dry. Rain is usually intermittent rather than relentless. Rain is the exception rather than the rule.
- Sun & UV - High UV at midday. Cloud cover doesn't always mean low UV, so still protect your skin. Shade breaks feel genuinely worthwhile.
- Exposure - Often breezy, and expect sharp gusts that can change plans in exposed areas. A light outer layer helps when you’re in the shade.
September in context
How it compares to the rest of the year in San Francisco.
Hottest (avg)
#1 / 12
Wettest (avg)
#10 / 12
Daylight Hours
#6 / 12
Windiest (avg)
#8 / 12
Highest UV
#6 / 12
Most Humid
#8 / 12
Temperature
- Daytime high
-
- Nighttime low
-
- Feels like (avg)
-
Sunshine
- Daylight
- 12.4 hours
- UV index (max)
- 7
- Typical sun hours
- 05:51 – 18:16
Rain & Snow
- Total
-
- Rainy days
- 1
- Cloud cover
- 36%
- Snowfall
-
Humidity & Wind
- Humidity (avg)
- 76%
- Wind (avg)
-
- Wind (max gusts)
-
Frequently asked questions
Is September a good time to visit San Francisco?
Typical September days in San Francisco reach highs of 22°C (72°F) with nights around 13°C (55°F). It usually feels warm by day and cool after dark. It is one of the drier months, which suits outdoor exploring and sightseeing.
What are temperatures like in September?
Daytime temperatures in September typically peak near 22°C (72°F), while nights drop to around 13°C (55°F). Expect warm afternoons and cool evenings.
How much does it rain in September?
Rainfall in September averages 3 mm (0.12 in) across roughly 1 days. Overall it is a mostly dry time of year, so showers are usually brief rather than all-day downpours.
How many hours of daylight are there in September?
You can expect about 12 hours of daylight in September. Sunrise is typically around 05:51 and sunset near 18:16. Daylight is fairly typical, with enough time for sightseeing.
How strong is the sun in September?
UV levels are often high (around 7). Regular sunscreen and a hat are recommended.
Is it windy in September?
In September, average wind speeds are around 13 km/h (8 mph), with gusts on the windiest days reaching about 51 km/h (32 mph). On the ground, it is it can feel quite windy at times, particularly when weather systems move through.