Today | Weather | Tuesday, April 21, 2026

Weather in Sunnyvale, California

03:58 PM
Now
Sunny with a Chance of Thunderstorms
63° F
Feels Like 57°
Precipitation 77 %
Wind 13 mph
UV Index (0 - 11+) 2
Humidity 67 %
Today
Stormy Weather
Day 64°
Night 50°
Precipitation 96 %
Wind 9 mph
UV Index (0 - 11+) 3

Sunnyvale Weather Forecast Updated

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

Day

77°

Night

52°

Wind

7 mph

UV Index

9

Precipitation

1 %

Air Quality in Sunnyvale

NOW
48 AQI
Good air quality Dominant pollutant: O3

Pollutant Concentrations:

PM2.5 0.52 µg/m³
PM10 1.32 µg/m³
O3 0.052 ppm
NO2 0.1 ppb
SO2 0.1 ppb
CO 0.12 ppm
NH3 0 µg/m³
NO 0.04 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)
PM2.50.52 µg/m³
PM101.32 µg/m³
O3102.51 µg/m³
NO20.22 µg/m³
SO20.34 µg/m³
CO141.83 µg/m³
NH30 µg/m³
NO0.04 µg/m³