UV Index Today in San Mateo County, California (CA)
Friday, May 22, 2026 -11:40 AMPDT (GMT-7)
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The average maximum UV Index today across 35 locations in San Mateo County, California (CA), is 8.5. The highest projected maximum is 8.7 in San Mateo at 1:00 PM PDT, while the lowest projected maximum is 7.7 in Pacifica at 1:00 PM PDT.
Tomorrow, the average maximum UV Index across those same locations is expected to be 8.6. The highest projected maximum is 8.8 in Portola Valley at 1:00 PM PDT, and the lowest projected maximum is 8.2 in Pacifica at 1:00 PM PDT.
35 Places in San Mateo County, California (CA)
Maximum UV Index Today