San Francisco Weather in September

September in San Francisco brings very high temperatures around 31°C (88°F) during the day, dropping to 26°C (79°F) at night, with the most rainfall of the year.

Rainfall in San Francisco in September

Expect the heaviest rain of the year this month, often arriving in intense bursts. A poncho is essential for keeping dry. Analyzing past climate data, one can expect approximately 18 days of rain, averaging 254 mm (10 in). This month brings frequent, heavy showers. Both the number of wet days and the rainfall totals are on the high side.

Temperature in San Francisco in September

Temperatures in San Francisco in September top out at 31°C (88°F) and drop to 26°C (79°F) overnight. Mornings and evenings are often more comfortable than the peak afternoon hours. With overnight lows of 26°C (79°F), nights stay very warm. Air conditioning makes a real difference if you're sensitive to heat. A cold shower before bed can also help you get to sleep more comfortably.

If you prefer dry days with pleasant temperatures, September may not be the ideal month to visit San Francisco. Our weather planner can help you explore destinations with more pleasant weather conditions.