San Francisco Weather in September

September in San Francisco brings high temperatures, with daytime highs of 23°C (73°F) and nights around 13°C (55°F). Only 3.4 mm (0.1 in) of rainfall is typical, making it a largely dry month.

Rainfall in San Francisco in September

Rain is expected on roughly a single day, totalling around 3.4 mm (0.1 in) for the month. Any rain that does arrive is likely to be light drizzle rather than a proper shower.

Temperature in San Francisco in September

The excellent temperature in San Francisco in September makes it a solid month to visit, with 23°C (73°F) during the day and 13°C (55°F) at night. Conditions stay fairly consistent through the month, making it easier to plan what to wear. Nights drop to around 13°C (55°F), which is noticeably cooler than the daytime. A light jacket for the evening is a sensible addition, and the cool nights tend to make sleeping comfortable. On average, it has the peak temperatures of the year.

Sunshine in San Francisco in September

Expect a lot of sunshine this month, with about 270 hours of sun. These sunny conditions add to the overall experience.

Wind Speed in San Francisco in September

Average wind conditions reach 5 m/s (10 knots) in September. This creates lively weather with fresh winds that make small trees sway noticeably. Remember this is an average: some days are less windy while others have particularly active windy conditions.

Average water temperature in September

The water is 14°C (57°F) this month, cool enough to feel refreshing on a warm day, but cold enough that most people won't stay in for long without a wetsuit.

If you favor pleasant temperatures and minimal rainfall, September is one of the best months to visit San Francisco.