North American wildfires intensify as climate change extends burning hours

North American wildfires are increasingly burning longer into the night as human-driven climate change extends the hot and dry conditions that fuel fires, according to new research. A study published in Science Advances found that favorable fire-weather hours across the region have surged by 36% over the past 50 years.

Extended fire hours are rising sharply across North America, with regions like California gaining an additional 550 burning hours annually compared to the 1970s. Parts of New Mexico and Arizona are seeing increases of up to 2,000 hours per year, reflecting how climate conditions are expanding the window for potential fires.

North American wildfires intensifies

North American wildfires are becoming more dangerous as they continue burning without the natural slowdown once caused by cooler, more humid conditions. Major incidents such as the Lahaina fire in Hawaii and recent blazes in Alberta and Los Angeles show how overnight fires are more difficult and risky for crews to control.

Fire seasons length expands significantly

Fire season length is also increasing, with the number of fire-prone days rising by 44% over the past half century—effectively adding nearly a month to the annual fire calendar. This shift is largely driven by warmer nights, drier air, and changing wind patterns.

Warming nights are playing a critical role in intensifying fire conditions, as higher overnight temperatures prevent humidity from recovering. According to National Oceanic and Atmospheric Administration, nighttime temperatures in the U.S. have risen faster than daytime highs since the 1970s, worsening fire susceptibility.

Drought conditions increase fire intensity

Drought conditions are further amplifying wildfire risks by drying out vegetation and creating highly flammable fuel. Scientists say hotter air pulls more moisture from plants and soil, creating a feedback loop that increases both the likelihood and severity of fires.