Today | Weather | Tuesday, August 4, 2026
Active Weather Warnings

Weather in San Jose, California

09:32 PM
Now
Cloudy Night
66° F
Feels Like 64°
Precipitation 0 %
Wind 6 mph
Humidity 78 %
Today
Cloudy Night
Day 84°
Night 61°
Precipitation 0 %
Wind 4 mph

San Jose Weather Forecast Updated

Last updated on
Weather Forecast History
Last Year's Weather on This Day (August 4, 2025)
Cloudy Night

Day

79°

Night

55°

Wind

5 mph

Precipitation

0 %

Air Quality in San Jose

NOW
52 AQI
Moderate air quality Dominant pollutant: PM2.5

Pollutant Concentrations:

PM2.5 13.08 µg/m³
PM10 31.8 µg/m³
O3 0.040 ppm
NO2 0.5 ppb
SO2 0.3 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 acceptable; however, for some pollutants, there may be a moderate health concern for a very small number of people who are unusually sensitive to air pollution.

Show raw pollutant concentrations (µg/m³)
PM2.513.08 µg/m³
PM1031.8 µg/m³
O377.97 µg/m³
NO20.88 µg/m³
SO20.91 µg/m³
CO83.74 µg/m³
NH30 µg/m³
NO0 µg/m³

Weather Alerts and Warnings for San Jose

Moderate Expected Likely

Heat Advisory

Heat Advisory issued August 4 at 9:14AM PDT until August 4 at 10:00PM PDT by NWS San Francisco CA
Aug 4, 10:00 AM Aug 4, 10:00 PM
WHAT: Temperatures in the 90s to low 100s.

WHERE: The Santa Clara Valley and Eastern Hills.

WHEN: Until 10 PM PDT this evening.

IMPACTS: This level of heat affects most individuals sensitive to
heat, especially those without effective cooling and/or adequate
hydration. Impacts possible in some health systems and in
heat-sensitive industries.

ADDITIONAL DETAILS: Hottest temperatures southern interior Santa
Clara Valley and interior Eastern Hills.
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Hydration is a critical piece to surviving the heat. Drink water, and if possible, take water to those who are vulnerable. Beat the heat and check the backseat! Do not leave young children or pets in unattended vehicles.Car interiors will reach lethal temperatures in a matter of minutes. Stay cool, stay hydrated, stay informed.
Updated: Aug 4, 8:07 PM Source: NWS Alert