California Unveils Lifesaving Heat-Ranking System, Invests $32 Million to Fight Extreme Heat

SACRAMENTO — Summer is around the corner and temperatures soared to record highs this past weekend.

Gov. Gavin Newsom in May announced the launch of CalHeatScore, a cutting-edge tool to forecast and rank heat severity risks and connect Californians with resources to stay safe during extreme heat events. With CalHeatScore, California becomes the first state in the nation —  and one of the only jurisdictions in the world —  to launch a heat-ranking system. The announcement comes as the Trump Administration makes life-threatening cuts to the federal government’s weather monitoring apparatus.

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 guidance. The tool identifies groups most susceptible to extreme heat —  such as older adults and children —  and provides tips for staying safe, such as how to recognize signs of heat illness. The tool additionally integrates other important data sets, like locations for the nearest cooling centers.

Gov. Newsom additionally announced $32.4 million to support 47 California communities in lifesaving extreme heat mitigation efforts. The Extreme Heat and Community Resilience Program aims to support local, tribal, and regional efforts to combat dangerous heat exposure by building long-lasting infrastructure solutions and strengthening community resilience needed to withstand extreme heat events.

In a hotter, drier world, connecting Californians with extreme weather information and resources has never been more important – especially as the federal government cuts critical programs providing pertinent information on weather.

First-in-the-nation heat-ranking tool

The new CalHeatScore tool will be leveraged across state government, providing early warning that allows resources to be mobilized with greater speed and precision to communities that need it. To ensure the new tool works for Californians, the state will continue gathering input from the public, which will be used to shape future updates. 

In 2021, the California Department of Insurance’s Climate Insurance Workgroup recommended California build a system to rank heat waves to better communicate the deadly risks to Californians and help communities prepare, similar to how tropical storms and hurricanes are described by “category” level. 

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