ReportMay 24, 2023

Wildfire Weather

Climate change is worsening wildfires across the United States and putting more people at risk. Warming from heat-trapping pollution is affecting weather conditions in ways that increase the risks of wildfire. Long-term warming trends are drying out forests, grasslands, and other landscapes—helping fires spread and hindering opportunities to fight and prevent them.

To explore growing wildfire risks across the U.S., Climate Central analyzed historical trends in fire weather—the combination of high heat, low humidity, and strong winds.

This analysis includes data from 476 weather stations to assess trends in 245 climate divisions spanning the contiguous states during a 50-year period (1973-2022). Results show that wildfire seasons are lengthening and intensifying, particularly during spring and summer in the West. Parts of Southern California and the Southwest are seeing around two additional months of fire weather compared to the early 1970s.

Annual fire weather days are also increasing in many parts of the East, although by fewer days on average than in the West. But even these smaller increases can be impactful in the densely populated East, where more people and property could be exposed. Seasonal trends are emerging in the East, with many areas experiencing more fire weather days during spring.

Significant differences in climate, topography, land use, and population distribution mean that wildfire risks are regionally distinct. But fire weather isn’t limited to the western U.S. As this analysis demonstrates, all U.S. regions experience conditions that increase the likelihood of more extreme fires.

As fire weather occurs more frequently, communities across the country must adapt to living with more frequent fire weather and the associated risks.

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