Climate Insights for San Francisco

The climate in San Francisco is warm and mild. The average annual temperature is 18°C and approximately 1007mm of precipitation falls per year. February is the wettest month, receiving around 286mm of rainfall. San Francisco is in the Southern Hemisphere. The seasons are reversed — summer runs from December to February, while winter falls between June and August. The summer months are: January, December, February. The coldest months are June, July, August, when temperatures can drop to 5°C.

Temperatures in San Francisco vary considerably across the year, with a 27°C difference between the coldest and warmest months. The warmest month is January, when average highs reach 32°C and the mean temperature sits around 26°C. June is the coolest month, with minimum temperatures around 5°C and an average of 9°C. On average, daily temperatures fluctuate by about 11°C between overnight lows and afternoon highs. The sharpest temperature change occurs between February and March, with a 5°C shift in average temperatures.

San Francisco is a moderately rainy area, receiving approximately 1007mm of precipitation annually, which averages out to around 84mm per month. The wettest month is February, averaging 286mm of rainfall. April and October also tend to see above-average precipitation. The driest month is September, with just 8mm. That's 278mm less than February, the wettest month. Rainfall is heavily concentrated in certain months, creating a distinct wet and dry season. Visitors should plan around these patterns, as the difference between peak and low months is dramatic.

San Francisco is relatively calm, with an average annual wind speed of 3km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is September, averaging 4km/h, though still comfortable for most outdoor activities. The calmest conditions occur in June, with average winds dropping to 3km/h, making it an ideal period for wind-sensitive activities. There is moderate seasonal variation in wind speed, with a 1km/h gap between the calmest and windiest months.

It is currently winter in San Francisco, which began on June 21, 2026. San Francisco is in the Southern Hemisphere, where the seasons are reversed — spring starts in September, summer in December, autumn in March, and winter in June. The warmest period peaks in January at around 32°C, while the coldest stretch bottoms out in June near 5°C. Spring is next, beginning on September 23, 2026 — 63 days from now.

The best time to visit San Francisco is during March, September and November, when the weather is most comfortable for travellers. During these months, average temperatures hover around 19°C with modest rainfall averaging 61mm per month. By contrast, January can be uncomfortably hot with highs reaching 32°C, while June is the coldest period with lows dropping to 5°C. A light rain jacket is recommended, though showers are generally brief and shouldn't disrupt your plans.

The table below shows monthly climate averages for San Francisco based on historical weather data. Min and max temperatures represent typical overnight lows and afternoon highs for each month, shown in degrees Celsius (°C). Precipitation is measured in millimetres (mm) and indicates the average total rainfall per month. Wind speed is the average sustained speed in kilometres per hour (km/h). All values are based on averages from over 10 years of historical weather data. The current month is highlighted for quick reference.