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

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As of 8:42 AM PST on December 29, 2025, all 33 cities in San Mateo County, CA in our database have a UV Index reading of Low. The city with the highest UV Index reading right now is San Mateo, CA with a reading of 0.1.

Over the next 24 hours, the highest UV Index reading in San Mateo County, CA is expected to be 2.1 in San Mateo between 12:00 PM - 1:00 PM PST today.

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Current UV Index in Cities in San Mateo County, CA

• Atherton - 0.1
• Baywood Park - 0.1
• Belmont - 0.1
• Brisbane - 0.1
• Broadmoor - 0.1
• Burlingame - 0.1
• Colma - 0.1
• Daly City - 0.1
• East Palo Alto - 0.1
• El Granada - 0.1
• Emerald Lake Hills - 0.1
• Foster City - 0.1
• Half Moon Bay - 0.1
• Highlands - 0.1
• Hillsborough - 0.1
• La Honda - 0.1
• Ladera - 0.1
• Loma Mar - 0.1
• Menlo Park - 0.1
• Millbrae - 0.1
• Montara - 0.1
• Moss Beach - 0.1
• North Fair Oaks - 0.1
• Pacifica - 0.1
• Pescadero - 0.1
• Portola Valley - 0.1
• Redwood City - 0.1
• San Bruno - 0.1
• San Carlos - 0.1
• San Mateo - 0.1
• South San Francisco - 0.1
• West Menlo Park - 0.1
• Woodside - 0.1