Gov. Newsom Expands Access to CalHeatScore to Keep Californians Safe During Extreme Heat

SACRAMENTO – Gov. Newsom May 21 announced a new feature to integrate California Communities Extreme Heat Scoring System (CalHeatScore) data into a wide range of applications to help Californians stay safe during extreme heat.

CalHeatScore, released last year, is a cutting-edge tool to forecast and rank the risk hot weather poses to public health and connect Californians with available resources to stay safe during extreme heat events.

About CalHeatScore

In a hotter, drier world, connecting Californians with extreme weather information and resources has never been more important.

As part of a broader climate package in 2022, Gov. Newsom signed Assembly Bill 2238 by Assemblymember Luz Rivas to codify the California Department of Insurance’s climate insurance workgroup recommendation by requiring the state to develop a statewide extreme heat ranking system.

In 2025, California became the first state in the nation – and one of the only jurisdictions in the world – to launch a heat-ranking system.

CalHeatScore, developed by the California Environmental Protection Agency’s office of environmental health hazard assessment or OEHHA, brings together ZIP-code level data to provide locally tailored heat scores. It translates complex weather and health data into clear guidance and integrates other important data sets, like locations for the nearest cooling centers. CalHeatScore also provides local data on groups susceptible to extreme heat, such as older adults and children, to support community planning efforts and provides tips for staying safe, such as how to recognize signs of heat illness.  

The API is part of continuous efforts to develop, improve and broaden options for using CalHeatScore and keep Californians informed about extreme heat in their communities.

In addition to CalHeatScore, you can learn more about actions you can take to protect yourself and others during extreme heat through Listos California and the California Department of Public Health.