Today | Weather | Friday, June 26, 2026

Weather in San Mateo, California

12:39 AM
Now
Cloudy Night
61° F
Feels Like 55°
Precipitation 40 %
Wind 9 mph
Humidity 90 %
Today
Cloudy Weather
Day 70°
Night 57°
Precipitation 7 %
Wind 14 mph
UV Index (0 - 11+) 10

Warning: High UV Index Today: 10

High risk of harm from unprotected sun exposure. Take precautions: wear a hat, sunglasses, and apply sunscreen regularly if you’ll be outdoors for extended periods.

San Mateo Weather Forecast Updated

Last updated on
Weather Forecast History
Last Year's Weather on This Day (June 26, 2025)
Cloudy Weather

Day

70°

Night

54°

Wind

12 mph

UV Index

11

Precipitation

0 %

Air Quality in San Mateo

NOW
32 AQI
Good air quality Dominant pollutant: O3

Pollutant Concentrations:

PM2.5 4.23 µg/m³
PM10 14.89 µg/m³
O3 0.034 ppm
NO2 0.4 ppb
SO2 0.4 ppb
CO 0.07 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)
PM2.54.23 µg/m³
PM1014.89 µg/m³
O367.38 µg/m³
NO20.66 µg/m³
SO21 µg/m³
CO81.37 µg/m³
NH30 µg/m³
NO0 µg/m³