California Shares Heat Risk Data for Apps

California is sharing its heat risk data with app makers. This is a new way to help people stay safe from extreme heat.
By Newsroom | Technology, Health |

The California administration has upgraded the CalHeatScore platform, adding an Application Programming Interface (API) that allows third-party developers, local governments, and weather services to ingest real-time, ZIP-code level heat risk metrics. This move follows the state’s 2025 launch of the system, which was initially supported by a $32.4 million allocation aimed at building regional resilience against temperature extremes.

The core utility of the system lies in its granular, location-specific ranking of heat severity, designed to bypass generalized forecasts and trigger targeted public health responses.

Technical Scope and Deployment

The platform serves as an early-warning mechanism intended to assist agencies in mobilizing resources—such as cooling centers and water distribution—before periods of intense thermal stress.

  • Data Granularity: The tool processes data at the ZIP-code level, rather than regional or county-wide tiers.

  • Accessibility: By providing an API, the state aims to decentralize the data, allowing independent developers to integrate heat-risk alerts into existing apps or digital services.

  • Strategic Context: The expansion occurs as part of the state's broader effort to formalize heat-ranking protocols, a move state officials framed as necessary to address shifts in federal weather monitoring support.

Operational Context and Policy Background

State leadership has positioned this tool as a necessary response to the fact that extreme heat remains a primary cause of weather-related mortality in the state. The Extreme Heat and Community Resilience Program, which provides the financial foundation for this effort, also encompasses physical infrastructure projects, including urban tree planting, the installation of reflective roofing, and the expansion of community cooling infrastructure.

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FeatureDescription
System NameCalHeatScore
Primary MetricZIP-code level heat severity risk
Funding SourceExtreme Heat and Community Resilience Program ($32.4M)
Target AudiencePublic, local governments, and third-party tech developers

The project is currently marketed as a first-of-its-kind initiative. While the state government promotes the tool as a primary method for mitigating health outcomes—including emergency room visits and chronic heat-related morbidity—the ongoing efficacy of the program relies on the ability of local jurisdictions to interpret and act upon the incoming data streams provided by the API.

Frequently Asked Questions

Q: What is the CalHeatScore platform update in California?
California has added a new feature to its CalHeatScore platform. This feature lets app makers and local governments get real-time heat risk information for specific areas.
Q: How does the CalHeatScore update help people in California?
This update helps by providing specific heat risk data down to the ZIP code level. This allows local groups to warn people and open cooling centers before dangerous heat arrives.
Q: How much money was spent on the CalHeatScore system?
The state spent $32.4 million to build and improve the CalHeatScore system. This money helps create ways to protect people from extreme heat.
Q: Who can use the new heat risk data from California?
App developers, local governments, and weather services can now use this data. They can use it to create warnings and services to keep people safe during hot weather.