California landscape

California

Population: 39.5M Updated Apr 20, 2026
Health Risks

COVID-19

Moderate
↓ Decreasing

COVID-19 is Low in Los Angeles, Sacramento, San Diego, San Jose, Palo Alto, and San Mateo, and High in San Francisco.

Flu

Very High
→ Stable

Flu is Moderate in Sacramento, San Diego, San Jose, and Palo Alto, High in Los Angeles and San Mateo, and Very High in San Francisco.

RSV

Low
↓ Decreasing

RSV is Low in Los Angeles, Sacramento, San Diego, San Jose, Palo Alto, and San Mateo, and High in San Francisco.

Infectious Diseases Risk

Very High
→ Stable

Infectious Diseases is Moderate in San Diego, High in Sacramento, San Jose, Palo Alto, and San Mateo, and Very High in Los Angeles and San Francisco.

Allergy

Very High
↑ Increasing

Allergy is Very High in Los Angeles, San Francisco, Sacramento, San Diego, San Jose, Palo Alto, and San Mateo.

Pollution

Low
→ Stable

Pollution is Low in Los Angeles, San Francisco, Sacramento, San Diego, San Jose, Palo Alto, and San Mateo.

Severe Weather

Low
↓ Decreasing

Severe Weather is Low in Los Angeles, San Francisco, Sacramento, San Diego, San Jose, Palo Alto, and San Mateo.
Counties
Alameda Alpine Amador Butte Calaveras Colusa Contra Costa Del Norte El Dorado Fresno Glenn Humboldt Imperial Inyo Kern Kings Lake Lassen Los Angeles Madera Marin Mariposa Mendocino Merced Modoc Mono Monterey Napa Nevada Orange Placer Plumas Riverside Sacramento San Benito San Bernardino San Diego San Francisco San Joaquin San Luis Obispo San Mateo Santa Barbara Santa Clara Santa Cruz Shasta Sierra Siskiyou Solano Sonoma Stanislaus Sutter Tehama Trinity Tulare Tuolumne Ventura Yolo Yuba
Published by Hubbub World — health risk data for all US states and counties. Get the bub app for today's data and 30-day forecasts.

Frequently Asked Questions

What health risks does Hubbub World track for California?
Hubbub World tracks seven health risks for California: flu, COVID-19, RSV, infectious diseases overall, seasonal allergies, air pollution, and severe weather. Each risk is broken out by county and updated weekly. For today's risk levels and 30-day forecasts, get the bub app at https://bub.hubbubworld.com.
How often is California health risk data updated?
Health risk data for California is regenerated weekly. Each hub page shows the six most recent weekly snapshots — the most recently completed week and the five preceding weeks. Today's risk levels and 30-day forecasts are not on the web; they are exclusive to the bub app at https://bub.hubbubworld.com.
What methodology does Hubbub World use?
Hubbub World develops proprietary models on top of the underlying surveillance, environmental, and weather data to produce comparable risk scores across all U.S. counties. Each of the seven risks is reported on a four-point scale (Low, Moderate, High, Very High) so the scores are interpretable without needing the raw underlying numbers. The full methodology — including the modeling approach, validation against authoritative sources, and known limitations — is documented at https://www.hubbubworld.com/intelligence#methodology. The health risk data on Hubbub World is for informational purposes only and does not constitute medical advice. Always consult a healthcare professional for personal health decisions.
Where can I get today's health risk data for California?
Today's health risk levels and 30-day forecasts for California are exclusive to the bub app, available free on iOS, Android, and Apple Watch at https://bub.hubbubworld.com. The web hub is the historical archive — for live data and forward-looking forecasts, the bub app is the source of truth.
Does Hubbub World cover counties in California?
Yes. Hubbub World tracks every county (and county-equivalent) in California, with weekly historical risk data for each. County pages are linked from this state page. For today's data and 30-day forecasts at the county level, get the bub app at https://bub.hubbubworld.com.

Last updated: April 20, 2026

Data refreshed weekly

Get today's California health risks — Download bub