Summary/Abstract
Climate change alters the frequency and intensity of wildfires, but its impact on the seasonal patterns of wildfires remains underexplored. Here, the authors quantify historical changes in wildfire seasonality across different ecoregions in North America and assess how climate change may affect these seasonal patterns. This study finds that boreal and taiga forests have experienced a clear advance in seasonal wildfire activity, whereas Mediterranean and desert regions show delayed and extended late-season burning. Prairie and humid forest regions exhibit comparatively muted change. Attribution analysis shows that atmospheric dryness is the dominant control, while antecedent temperature, precipitation, and soil moisture indirectly shape wildfire risk through vegetation and fuel continuity at different lag times. These findings provide a basis for interpreting future region-specific changes in wildfire seasonality and emphasize the need for region-specific assessments of future wildfire activity.