Today | Weather | Thursday, May 21, 2026

Weather in Santa Rosa, California

08:19 AM
Now
Cloudy Weather
57° F
Feels Like 61°
Precipitation 0 %
Wind 2 mph
UV Index (0 - 11+) 1
Humidity 75 %
Today
Cloudy Weather
Day 86°
Night 48°
Precipitation 0 %
Wind 7 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.

Santa Rosa Weather Forecast Updated

Last updated on
Weather Forecast History
Last Year's Weather on This Day (May 21, 2025)
Sunny Weather

Day

84°

Night

46°

Wind

6 mph

UV Index

10

Precipitation

1 %

Air Quality in Santa Rosa

NOW
40 AQI
Good air quality Dominant pollutant: O3

Pollutant Concentrations:

PM2.5 5.14 µg/m³
PM10 17.36 µg/m³
O3 0.043 ppm
NO2 0.5 ppb
SO2 0.3 ppb
CO 0.11 ppm
NH3 0.04 µg/m³
NO 0.08 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)
PM2.55.14 µg/m³
PM1017.36 µg/m³
O384.16 µg/m³
NO21.02 µg/m³
SO20.91 µg/m³
CO126.57 µg/m³
NH30.04 µg/m³
NO0.08 µg/m³