Today | Weather | Saturday, August 29, 2026

Weather in San Mateo, California

10:09 PM
Now
Cloudy Night
63° F
Feels Like 57°
Precipitation 0 %
Wind 12 mph
Humidity 78 %
Today
Cloudy Night
Day 75°
Night 57°
Precipitation 2 %
Wind 9 mph

San Mateo Weather Forecast Updated

Last updated on
Weather Forecast History
Last Year's Weather on This Day (August 29, 2025)
Cloudy Night

Day

79°

Night

55°

Wind

8 mph

Precipitation

0 %

Air Quality in San Mateo

NOW
32 AQI
Good air quality Dominant pollutant: O3

Pollutant Concentrations:

PM2.5 3.87 µg/m³
PM10 14.52 µg/m³
O3 0.034 ppm
NO2 0.3 ppb
SO2 0.2 ppb
CO 0.09 ppm
NH3 0 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:

Air quality is considered satisfactory, and air pollution poses little or no risk.

Show raw pollutant concentrations (µg/m³)
PM2.53.87 µg/m³
PM1014.52 µg/m³
O367.24 µg/m³
NO20.53 µg/m³
SO20.57 µg/m³
CO107.46 µg/m³
NH30 µg/m³
NO0 µg/m³