San Mateo, California Weather:
Active Weather Warnings
Monday, October 5, 2026
Sunny Weather
Day 90°
Night 63°
Precipitation 0 %
Wind 7 mph
UV Index (0 - 11+) 5
Weather Forecast History
Last Year's Weather on This Day (October 5, 2025)
Cloudy Night

Day

79°

Night

55°

Wind

5 mph

Precipitation

0 %

Weather Alerts and Warnings for

Moderate Expected Likely

Heat Advisory

Heat Advisory issued October 3 at 7:48PM PDT until October 7 at 10:00PM PDT by NWS San Francisco CA
Oct 3, 7:48 PM → Oct 7, 10:00 PM
WHAT: Hot conditions with maximum temperatures in the mid-90s to
low-100s. Mild minimum temperatures and weak onshore flow will
limit overnight relief.

WHERE: The East Bay and San Francisco Bay Shoreline, North Bay
Interior Mountains and Valleys, The Santa Clara Valley and Eastern
Hills, The Santa Cruz Mountains, Interior Monterey County and the
Santa Lucia Range, Most of San Benito County and the Cholame Hills
in Southeast Monterey County, and Southern Salinas Valley/Arroyo
Seco and Lake San Antonio.

WHEN: Until 10 PM PDT Wednesday.

IMPACTS: This level of heat affects anyone without effective
cooling and/or adequate hydration. Impacts likely in some health
systems, heat-sensitive industries and infrastructure.
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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. Take extra precautions when outside. Wear lightweight and loose fitting clothing. Try to limit strenuous activities to the early morning or evening. Take action when you experience symptoms of heat exhaustion and/or heat stroke. 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.
Updated: Oct 4, 2:04 PM Source: NWS Alert