The CDR weather data provides monthly measures of heat index categories, wind chill index categories, precipitation, and average temperatures. These measures are available from 1979 to 2023. The measures are calculated from gridMET, which provides daily high-resolution meteorological data. CDR interpolated gridMET data to the census tract level and aggregated the data to produce monthly measures.
Heat Index: Number of Heat Days at Extreme Caution+ Level (≥90°F) in 2016
Wind Chill Index: Number of Cold Days at Wind Chill Index Values ≤ 0°F in 2016
Data Summary
Dataset Name: gridMET
Data Source: John T. Abatzoglou Climatology Lab, University of California Merced
Years: All data contains measures between 1979 and 2023
Geographies: Census Tract
Documentation: PDF for gridMET
Suggested Citation:
Ailshire, J.A., Nam, J. W., Vavra-Musser, K., Choi, E.Y., Fisk, C.E. 2025. Contextual Data Resource (CDR): gridMET Weather Data. Los Angeles, CA: USC/UCLA Center on Biodemography and Population Health.
Related Publications
Choi, E. Y., & Ailshire, J. A. (2025). Ambient outdoor heat and accelerated epigenetic aging among older adults in the US. Science Advances, 11(9), eadr0616. https://doi.org/10.1126/sciadv.adr0616
Data Sources
John T. Abatzoglou Climatology Lab, University of California Merced
http://www.climatologylab.org/gridmet.html
Abatzoglou, J.T. (2013), Development of gridded surface meteorological data for ecological applications and modelling. International Journal of Climatology, 33(1), 121–131.