Climate and weather greatly influence wildfire, and recent increases in wildfire activity have been linked to climate change. However, the atmospheric drivers of observed changes have not been articulated globally. We present a global analysis of trends in extreme fire weather from 1979–2020. Significant increases in extreme (95th percentile) annual values of the Fire Weather Index (FWI95), Initial Spread Index (ISI95), and Vapour Pressure Deficit (VPD95) occurred over 26.0%, 26.1%, and 46.1% of the global burnable landmass, respectively. Significant trends corresponded to a 35.8%, 36.0%, and 21.4% increase in mean global FWI95, ISI95, and VPD95, respectively. Relative humidity and temperature were identified as the drivers of significant trends in FWI95 and ISI95 in most regions, largely where temperature trends outpaced dew point trends. We identified relatively few regions in which wind speed or precipitation were drivers. These findings have wide-ranging implications for understanding fire risk in a changing climate.