Climate Overview
The climate in San Francisco International Airport is temperate. The average annual temperature is 14°C and approximately 551mm of precipitation falls per year. January is the wettest month, receiving around 141mm of rainfall. San Francisco International Airport is in the Northern Hemisphere. Summer begins at the end of June and lasts through September. The summer months are: September, October, August. The coldest months are December, February, January, when temperatures can drop to 8°C.
Temperature
San Francisco International Airport sees moderate temperature variation throughout the year, ranging from 8°C to 23°C. September is the warmest month, though highs remain moderate at 23°C with a mean of 18°C. December is the coolest month, with minimum temperatures around 8°C and an average of 11°C. Daily temperature variation is modest, with an average difference of 8°C between highs and lows. The sharpest temperature change occurs between October and November, with a 3°C shift in average temperatures.
Precipitation
San Francisco International Airport is a relatively dry area, receiving approximately 551mm of precipitation annually, which averages out to around 46mm per month. The wettest month is January, averaging 141mm of rainfall. February and March also tend to see above-average precipitation. The driest month is July, with just 1mm. That's 140mm less than January, 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.
Wind
San Francisco International Airport 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 June, averaging 4km/h, though still comfortable for most outdoor activities. The calmest conditions occur in November, with average winds dropping to 2km/h, making it an ideal period for wind-sensitive activities. There is moderate seasonal variation in wind speed, with a 2km/h gap between the calmest and windiest months.
Seasons
4 days until Summer
It is currently spring in San Francisco International Airport, which began on March 20, 2026. San Francisco International Airport is in the Northern Hemisphere, where spring begins in March, summer in June, autumn in September, and winter in December. The warmest period peaks in September at around 23°C, while the coldest stretch bottoms out in December near 8°C. Summer is next, beginning on June 21, 2026 — 4 days from now.
Spring
Temperatures range from 10 to 19°C. Precipitation is moderate at around 157mm for the season, averaging 52mm per month. Winds are generally light, averaging 3km/h. Light layers work well as temperatures warm through the season — a great time to be outdoors.
Summer
Temperatures range from 13 to 22°C. Precipitation is minimal, with only around 4mm for the entire season. Winds are generally light, averaging 4km/h. Comfortable clothing with a light layer for cooler evenings is all you need.
Autumn
Temperatures range from 10 to 23°C. Rainfall is relatively light, with around 77mm over the season and a monthly average of 26mm. Winds are generally light, averaging 3km/h. Layered clothing works best as temperatures gradually cool — enjoy the crisp air and changing scenery.
Winter
Temperatures range from 8 to 16°C. Rainfall is heavy, totalling around 313mm across the season with a monthly average of 104mm. Winds are generally light, averaging 3km/h. A light jacket or sweater is usually sufficient, though cooler evenings may call for an extra layer.
Best Time to Visit
The best time to visit San Francisco International Airport is during June, July, August, September and October, when the weather is most comfortable for travellers. During these months, average temperatures hover around 17°C with modest rainfall averaging 6mm per month. By contrast, December can be quite cold with temperatures dropping to 8°C. With minimal rainfall expected, you can pack light and plan outdoor activities with confidence.
Monthly Climate Data
The table below shows monthly climate averages for San Francisco International Airport 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.
