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

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As of 3:36 PM PDT on July 29, 2026, out of 33 cities in San Mateo County, CA in our database, 21 cities (64%) have a UV Index reading of Very High, while 12 cities (36%) have a UV Index reading of High. The city with the highest UV Index reading right now is Portola Valley, CA with a reading of 7.8.

Over the next 24 hours, the highest UV Index reading in San Mateo County, CA is expected to be 10.8 in Portola Valley between 1:00 PM - 2:00 PM PDT tomorrow.

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Current UV Index in Cities in San Mateo County, CA

• Atherton - 7.7
• Baywood Park - 7.7
• Belmont - 7.7
• Brisbane - 7.2
• Broadmoor - 7.2
• Burlingame - 7.7
• Colma - 7.2
• Daly City - 7.2
• East Palo Alto - 7.7
• El Granada - 7.3
• Emerald Lake Hills - 7.7
• Foster City - 7.7
• Half Moon Bay - 7.3
• Highlands - 7.7
• Hillsborough - 7.7
• La Honda - 7.8
• Ladera - 7.7
• Loma Mar - 7.8
• Menlo Park - 7.7
• Millbrae - 7.3
• Montara - 7.3
• Moss Beach - 7.3
• North Fair Oaks - 7.7
• Pacifica - 7.3
• Pescadero - 7.8
• Portola Valley - 7.8
• Redwood City - 7.7
• San Bruno - 7.2
• San Carlos - 7.7
• San Mateo - 7.7
• South San Francisco - 7.2
• West Menlo Park - 7.7
• Woodside - 7.7