Wildfires Burning Longer Into the Night, New Study Finds

Wildfire season is approaching, and a new study is raising concerns about how fires behave overnight. Researchers have found that wildfires across North America are no longer slowing down at night the way they once did, giving fire crews fewer hours to make progress against the flames.

Wildfires No Longer Slow Down at Night

Wildfires have traditionally followed a predictable cycle, gaining strength during the heat of the day and easing after sunset. Cooler overnight temperatures and rising humidity once helped slow the spread of flames by adding moisture back to dry vegetation.

That pattern is changing. A study published in Science Advances found that the number of fire-friendly weather hours in North America has increased 36% over the past five decades. The western United States has seen the most pronounced increase.