The compound nature of large wildfires affected by multiple natural and anthropogenic factors in combination with complex interactions involved in hydroclimate-related physical processes make it difficult to directly connect wildfire changes over fire-prone regions like the western United States (U.S.) with anthropogenic climate change. Here we show that increasing large wildfires during autumn over the western U.S. are fueled by more fire-favorable weather associated with rapid declines in Arctic sea ice during preceding months on both interdecadal and interannual time scales. Our analysis (based on observations, climate model sensitivity experiments, and a multi-model ensemble of climate simulations) demonstrates and explains the Arctic-driven teleconnection through circulation changes with the poleward-shifted North Pacific jet stream and enhanced fire-favorable surface weather conditions. The amplitude of the Arctic-driven fire weather change is of similar magnitude to other leading modes of climate variability such as the El Niño-Southern Oscillation (ENSO) that also influence fire weather in the western U.S.