Climate Overview
The climate in San Mateo is hot. The average annual temperature is 28°C and approximately 873mm of precipitation falls per year. August is the wettest month, receiving around 156mm of rainfall. San Mateo sits near the equator, so seasonal temperature differences are minimal throughout the year.
Temperature
San Mateo sees moderate temperature variation throughout the year, ranging from 22°C to 36°C. April is the hottest month, with daytime highs reaching 36°C and an average of 30°C. January is the coolest month, with minimum temperatures around 22°C and an average of 28°C. On average, daily temperatures fluctuate by about 10°C between overnight lows and afternoon highs.
Precipitation
San Mateo is a moderately rainy area, receiving approximately 873mm of precipitation annually, which averages out to around 73mm per month. The wettest month is August, averaging 156mm of rainfall. July and September also tend to see above-average precipitation. The driest month is February, with just 10mm. That's 146mm less than August, 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 mildly breezy, with an average annual wind speed of 12km/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 15km/h, though still comfortable for most outdoor activities. The calmest conditions occur in August, with average winds dropping to 10km/h, making it an ideal period for wind-sensitive activities. There is moderate seasonal variation in wind speed, with a 5km/h gap between the calmest and windiest months.
Seasons
89 days until Summer
It is currently spring in San Mateo, which began on March 20, 2026. San Mateo sits near the equator, so the traditional four-season cycle is less pronounced — temperatures remain relatively stable year-round. The warmest period peaks in April at around 36°C, while the coldest stretch bottoms out in January near 22°C. Summer is next, beginning on June 21, 2026 — 89 days from now.
Spring
Temperatures range from 24 to 36°C. Rainfall is relatively light, with around 105mm over the season and a monthly average of 35mm. Winds are generally light, averaging 14km/h. Light layers work well as temperatures warm through the season — a great time to be outdoors.
Summer
Temperatures range from 24 to 33°C. Rainfall is heavy, totalling around 416mm across the season with a monthly average of 139mm. Winds are generally light, averaging 11km/h. Light, breathable clothing is ideal — perfect conditions for outdoor activities.
Autumn
Temperatures range from 24 to 34°C. Precipitation is moderate at around 294mm for the season, averaging 98mm per month. Winds are generally light, averaging 11km/h. A waterproof jacket and sturdy footwear are recommended as rain becomes more frequent.
Winter
Temperatures range from 22 to 35°C. Rainfall is relatively light, with around 58mm over the season and a monthly average of 19mm. Winds are generally light, averaging 13km/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.
