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

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As of 4:59 AM PDT on August 22, 2025, all 33 cities in San Mateo County, CA in our database have a UV Index reading of 0, indicating no radiation from the sun.

Over the next 24 hours, the highest UV Index reading in San Mateo County, CA is expected to be 9.4 in Portola Valley between 1:00 PM - 2:00 PM PDT today.

Search Cities in San Mateo County, CA

Current UV Index in Cities in San Mateo County, CA

• Atherton - 0
• Baywood Park - 0
• Belmont - 0
• Brisbane - 0
• Broadmoor - 0
• Burlingame - 0
• Colma - 0
• Daly City - 0
• East Palo Alto - 0
• El Granada - 0
• Emerald Lake Hills - 0
• Foster City - 0
• Half Moon Bay - 0
• Highlands - 0
• Hillsborough - 0
• La Honda - 0
• Ladera - 0
• Loma Mar - 0
• Menlo Park - 0
• Millbrae - 0
• Montara - 0
• Moss Beach - 0
• North Fair Oaks - 0
• Pacifica - 0
• Pescadero - 0
• Portola Valley - 0
• Redwood City - 0
• San Bruno - 0
• San Carlos - 0
• San Mateo - 0
• South San Francisco - 0
• West Menlo Park - 0
• Woodside - 0