Abstract Wildfire activity has increased across the western United States (US), with evidence linking these trends to anthropogenic climate forcing. Here, we analyze the frequency, intensity, and drivers of fire weather extremes in the southwestern US over the past 83 years. These extremes exhibit strong seasonality: wintertime changes align with long-term warming trends, while summertime variations are dominated by decadal fluctuations modulated by the Pacific Decadal Oscillation (PDO).