CalHeatScore

About the Tool

The California Communities Extreme Heat Scoring System (CalHeatScore) is designed to help Californians stay healthy when temperatures rise by:

Forecasting upcoming heat waves
Helping people prepare and plan for extreme heat events
Providing information about local resources

CalHeatScore, developed by the California Environmental Protection Agency’s Office of Environmental Health Hazard Assessment (OEHHA), uses historical climate, forecasted weather, and health data to score heat events based on their intensity and potential health impacts. Every day, CalHeatScore creates an easy-to-understand scale of 0 to 4 for all ZIP codes in California to communicate heat risks. CalHeatScore also connects people to locally relevant resources, such as cooling centers, so that they can be prepared when dangerous heat occurs.

Share your feedback

Cohort Consultation

From July-October 2025, we gathered feedback on the CalHeatScore Tool by working with community experts who provided local knowledge and recommendations to improve the tool and enable its use within communities most vulnerable to heat. The UCLA Luskin Center for Innovation is incorporating this feedback into a User Guide that provides general guidance to accompany the use of the CalHeatScore tool.

Cohorts focused on three groups vulnerable to heat illness:

Outdoor & Warehouse Workers
Older Adults
California Native Tribes

Cohort FAQs

Project Partners

LARC worked with the Office of Environmental Health Hazard Assessment (OEHHA) and the Governor's Office of Land Use and Climate Innovation (LCI) to create a space for community experts to share ideas on how CalHeatScore can be integrated into existing extreme heat practices and used these recommendations to develop CalHeatScore training materials.

The UCLA Luskin Center for Innovation developed a heat warning system guide, which incorporate findings from the user cohorts.