San Mateo County, CA: Current UV Index and Hourly Forecast

As of 5:54 PM PDT on June 13, 2025, all 33 cities in San Mateo County, CA in our database have a UV Index reading of Moderate. The city with the highest UV Index reading right now is Portola Valley, CA with a reading of 3.3.

Over the next 24 hours, the highest UV Index reading in San Mateo County, CA is expected to be 8.8 in Portola Valley between 1:00 PM - 2:00 PM PDT tomorrow.

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UV Index Risk Levels
Range0 - 23 - 56 - 78 - 1011+
Color
RiskLowModerateHighVery HighExtreme
UV Index in San Mateo County, CA as of 5:54 PM PDT, June 13, 2025

Current UV Index in Cities in San Mateo County, CA

5:54 PM PDT, June 13, 2025