Climate Overview
The climate in San Mateo is temperate. The average annual temperature is 15°C and approximately 538mm of precipitation falls per year. January is the wettest month, receiving around 113mm of rainfall. San Mateo is in the Northern Hemisphere. Summer begins at the end of June and lasts through September. The summer months are: September, August, October. The coldest months are February, December, January, when temperatures can drop to 8°C.
Temperature
San Mateo sees moderate temperature variation throughout the year, ranging from 8°C to 24°C. September is the warmest month, though highs remain moderate at 24°C with a mean of 18°C. February 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 Mateo is a relatively dry area, receiving approximately 538mm of precipitation annually, which averages out to around 45mm per month. The wettest month is January, averaging 113mm of rainfall. March and December also tend to see above-average precipitation. The driest month is July, with just 0mm. That's 113mm 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 Mateo is relatively calm, with an average annual wind speed of 8km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is May, averaging 10km/h, though still comfortable for most outdoor activities. The calmest conditions occur in October, with average winds dropping to 7km/h, making it an ideal period for wind-sensitive activities. There is moderate seasonal variation in wind speed, with a 3km/h gap between the calmest and windiest months.
Seasons
7 days until Autumn
It is currently summer in San Mateo, which began on June 21, 2026. San Mateo 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 24°C, while the coldest stretch bottoms out in February near 8°C. Autumn is next, beginning on September 23, 2026 (7 days from now).
Spring
Temperatures range from 9 to 20°C. Rainfall is relatively light, with around 150mm over the season and a monthly average of 50mm. Winds are generally light, averaging 9km/h. Light layers work well as temperatures warm through the season. It is a great time to be outdoors.
Summer
Temperatures range from 13 to 23°C. Precipitation is minimal, with only around 2mm for the entire season. Winds are generally light, averaging 8km/h. Comfortable clothing with a light layer for cooler evenings is all you need.
Autumn
Temperatures range from 10 to 24°C. Rainfall is relatively light, with around 82mm over the season and a monthly average of 27mm. Winds are generally light, averaging 7km/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 304mm across the season with a monthly average of 101mm. Winds are generally light, averaging 8km/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 Mateo 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, February 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 Mateo 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.
