North American wildfires are occurring over longer periods, beginning earlier in the year, and continuing into night-time hours. Research published in 2026 has linked these changes to rising temperatures and altered atmospheric conditions across the continent.
Fire Calendar
The term fire calendar refers to the annual timing of wildfire activity in a region. In North America, the calendar has shifted towards earlier ignition dates, longer burning periods, and extended seasonal activity in several forested and western areas.
Observed Changes in Burning Hours
Between 1975 and 2024, annual potential burning hours in North America increased by 36%. Western regions recorded rises of 48% to 57% in spring and autumn burning hours during the same period.
Regional Pattern of Wildfire Seasons
Northern forests, including Alaska, Canada, and the Great Lakes region, have seen wildfire seasons begin earlier. Parts of the western United States and California have recorded later seasonal endings, while prairie regions have shown limited change in seasonal timing.
Night-time Fire Activity
Warmer nights reduce forest recovery after daytime heat and dryness. This condition allows some fires to remain active after sunset, as seen in the 2023 Maui fire, the 2024 Jasper fire in Alberta, and the 2025 Los Angeles fires.
Recent Fire Statistics
As of 27 March 2026, the United States had recorded more than 15,000 wildfire ignitions and over 1.5 million acres burned. This acreage was 127% above the 10-year average for the same period and ranked first for ignitions in the past decade. In 2025, the United States had more than 44,470 fires and over 3.9 million acres burned by 21 August. Canada recorded 18.5 million acres burned in 2025, which was its second-worst wildfire season on record.
Risk Forecasts and Insurance Impact
In January 2026, the National Interagency Fire Center projected above-normal wildfire risk for Texas, Florida, Georgia, the Carolinas, and much of the south-eastern United States. The forecast was linked to persistent atmospheric patterns resembling La Niña.
Last Modified: April 21, 2026