Infectious risk activity has been stable over the past 12 weeks in San Mateo, California.
Allergy risk activity has been increasing over the past 12 weeks in San Mateo, California.
No Pollution activity has been reported over the past 12 weeks in San Mateo, California.
Weather risk activity has been increasing over the past 12 weeks in San Mateo, California.
Last updated: May 24, 2026
Data refreshed weekly