California COVID-19 and Influenza Model Projections for 2025

Three tables contain model-based projections for California state, regions, and counties from the CalCAT platform in 2025. The data includes COVID-19 R-effective estimates for the past 80 days, 4-week forecasts for hospital census and admissions, and variant proportion nowcasts for the past 3 months. It is produced by the California Department of Public Health.

Use Cases

• Analyze trends in COVID-19 transmission by comparing R-effective estimates across California counties over the past 80 days.
• Forecast hospital resource needs using the 4-week horizon projections for COVID-19 and Influenza hospital census and admissions.
• Monitor the prevalence of COVID-19 variants of concern using the Integrated Genomic Epidemiology Dataset (IGED)-based and Terra-based proportion estimates.
• Evaluate forecast model performance by comparing ensemble metrics against individual model projections for hospital admissions.

Strengths

• Includes three distinct, regularly updated projection tables for key public health metrics.
• Provides data at multiple geographic levels: state, regions, and counties for California.
• Covers two major respiratory diseases (COVID-19 and Influenza) with forecasts for a 4-week horizon.
• Includes historical archives of projections dating back through 2023 for longitudinal analysis.

Limitations

• The exact row count and granularity of daily records per location are unknown.
• Projection accuracy is model-dependent and subject to uncertainty, especially for longer forecast horizons.
• Data is specific to California, limiting applicability for national or international comparative studies.

Provenance

Source

California Department of Public Health (CDPH) CalCAT modeling platform.

Collection Method

Model-based projections and estimates generated by epidemiological models and ensembles.

Time Range

Projections are centered on 2025, with historical archives through 2023. Nowcasts cover the past 80 days and 3 months.

Freshness

Updated to an archive date in 2025, with a platform update recorded in March 2026.

Geography

California, United States, with data for state, regions, and counties.