Climate Central has examined historical trends in fire weather — a combination of low humidity, high heat, and strong winds — across the U.S., using data from 476 weather stations to assess trends in 245 climate divisions spanning all 48 contiguous states over a 50-year period from 1973 to 2022.
Wildfire seasons have become longer and more intense, especially across the West, and the research also found that many parts of the East have experienced smaller but important increases in fire weather. Even small increases in the East — with almost 28 million homes in fire-prone areas — puts millions more people at increased risk. As the research intro points out, the same weather variables that influence fire weather and wildfire are factors that determine the safe use of prescribed fire, critical to reducing fuels and thus fire risk. More fire weather days means fewer windows for prescribed burning.
The reports include both summaries and in-depth comparisons of Fifty Years of Fire Weather in the West (example: Some places, including parts of Texas, California, Oregon, and Washington, are experiencing fire weather more than twice as often now as in the early 1970s) and Fifty Years of Fire Weather in the East (example: New England has experienced a decrease in annual fire weather days, driven largely by fewer days in which the wind speed variable hit the analytical threshold). Reduced wind speeds could be partially attributed to a decrease in the temperature gradient between land and sea along the Gulf of Maine, as sea surface temperatures have warmed drastically due to climate change.
Climate Central’s new report, Wildfire Weather: Analyzing the 50-year shift across America, expands on wildfire risks and adaptation across the country. The full report discusses other key factors that influence wildfire, including fuels, other weather conditions, and human activity.
