Today | Weather | Thursday, February 5, 2026

Weather in San Mateo, California

05:34 PM
Now
Cloudy Night
64° F
Feels Like 64°
Precipitation 0 %
Wind 5 mph
Humidity 61 %
Today
Cloudy Weather
Day 70°
Night 48°
Precipitation 0 %
Wind 4 mph
UV Index (0 - 11+) 3

San Mateo Weather Forecast Updated

29 minutes ago
Last updated on
Weather Forecast History
Last Year's Weather on This Day (February 5, 2025)
Cloudy Weather

Day

59°

Night

46°

Wind

7 mph

UV Index

3

Precipitation

1 %

Air Quality in San Mateo

NOW
149 AQI
Unhealthy air quality for sensitive groups Dominant pollutant: PM2.5

Pollutant Concentrations:

PM2.5 54.99 µg/m³
PM10 58.85 µg/m³
O3 0.057 ppm
NO2 1.7 ppb
SO2 0.4 ppb
CO 0.30 ppm
NH3 0.35 µg/m³
NO 0 µg/m³
PM2.5 – Fine particles <2.5μm
PM10 – Inhalable particles <10μm
O3 – Ozone
NO2 – Nitrogen dioxide
SO2 – Sulfur dioxide
CO – Carbon monoxide
NH3 – Ammonia
NO – Nitric oxide

Health Recommendations:

Members of sensitive groups may experience health effects. The general public is not likely to be affected.

Show raw pollutant concentrations (µg/m³)
PM2.554.99 µg/m³
PM1058.85 µg/m³
O3111.81 µg/m³
NO23.23 µg/m³
SO21.16 µg/m³
CO342.2 µg/m³
NH30.35 µg/m³
NO0 µg/m³