Flu in California

Flu (influenza) is a contagious respiratory illness caused by influenza viruses. Symptoms range from mild to severe and can include fever, cough, sore throat, body aches, and fatigue. Hubbub World's flu risk score reflects the modeled burden of influenza activity in a given area, validated against CDC surveillance data.

Flu risk in California is reported as a weekly score on a four-point scale: Low, Moderate, High, and Very High. The score reflects the modeled burden of Flu across the state, validated against public health data from CDC, HHS, NOAA, and other authoritative sources. Methodology details are available at https://www.hubbubworld.com/intelligence#methodology.

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.

Current Flu 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. This web page is the six-week historical archive — the bub app is where today's data and forecasts live.

Several of the risks Hubbub World tracks have a seasonal pattern in California — flu and RSV typically peak in fall and winter, allergies vary with tree, grass, and weed pollen seasons, and severe weather risks shift with the calendar. Flu risk in California is reported weekly so seasonal patterns are visible across the six-week archive on this page. For 30-day forward forecasts that show how seasonal patterns are evolving, get the bub app at https://bub.hubbubworld.com.