South San Francisco Weather in September

During September, South San Francisco experiences high daytime temperatures of 23°C (73°F) and cooler nights around 13°C (55°F). Rainfall is low, averaging just 3.7 mm (0.1 in) for the month.

Rainfall in South San Francisco in September

Typically, you can expect about a single day of rain this month, with 3.7 mm (0.1 in) on average. On the rare occasion it rains this month, it usually amounts to very little.

Temperature in South San Francisco in September

The excellent temperature in South 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. This kind of day-to-night contrast is typical for this time of year. With overnight lows of 13°C (55°F), evenings can feel noticeably cooler than the daytime. An extra layer is a good idea, though the cool air makes for a good night's sleep. On average, it has the peak temperatures of the year.

Sunshine in South San Francisco in September

There are approximately 270 hours of sunshine this month, resulting in mostly clear days.

Wind Speed in South 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 temperature is 14°C (57°F), chilly, but perfectly fine for a swim if you're not too sensitive to cold water. A short wetsuit can make longer sessions more comfortable.

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