Climate Overview
The climate in San Mateo is hot. The average annual temperature is 27°C and approximately 2485mm of precipitation falls per year. San Mateo receives a notable amount of rainfall throughout the year, including during its driest month. San Mateo is in the Northern Hemisphere. Summer begins at the end of June and lasts through September. The summer months are: June, May, July. The coldest months are February, January, March, when temperatures can drop to 21°C.
Temperature
San Mateo sees moderate temperature variation throughout the year, ranging from 21°C to 35°C. The warmest month is June, when average highs reach 35°C and the mean temperature sits around 29°C. February is the coolest month, with minimum temperatures around 21°C and an average of 24°C. Daily temperature variation is modest, with an average difference of 7°C between highs and lows. The sharpest temperature change occurs between March and April, with a 2°C shift in average temperatures.
Precipitation
San Mateo is a very wet location, receiving approximately 2485mm of precipitation annually, which averages out to around 207mm per month. The wettest month is July, averaging 326mm of rainfall. August and December also tend to see above-average precipitation. The driest month is April, with just 59mm. That's 267mm less than July, 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 1km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is December, averaging 2km/h, though still comfortable for most outdoor activities. The calmest conditions occur in May, with average winds dropping to 1km/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.
Seasons
92 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 June at around 35°C, while the coldest stretch bottoms out in February near 21°C. Autumn is next, beginning on September 23, 2026 — 92 days from now.
Spring
Temperatures range from 22 to 34°C. Rainfall is heavy, totalling around 367mm across the season with a monthly average of 122mm. Winds are generally light, averaging 1km/h. An umbrella or waterproof jacket is advisable as spring showers are frequent.
Summer
Temperatures range from 25 to 35°C. Rainfall is heavy, totalling around 814mm across the season with a monthly average of 271mm. Winds are generally light, averaging 1km/h. Light, breathable clothing is ideal — perfect conditions for outdoor activities.
Autumn
Temperatures range from 23 to 32°C. Rainfall is heavy, totalling around 760mm across the season with a monthly average of 253mm. Winds are generally light, averaging 2km/h. A waterproof jacket and sturdy footwear are recommended as rain becomes more frequent.
Winter
Temperatures range from 21 to 28°C. Rainfall is heavy, totalling around 544mm across the season with a monthly average of 181mm. Winds are generally light, averaging 2km/h. A light jacket or sweater is usually sufficient, though cooler evenings may call for an extra layer.
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.
