Why it matters: Warmer springs can heighten wildfire risks and worsen allergies, among other effects.
How it works: Nonprofit climate research and communications organization Climate Central examined 55 years of U.S. temperature data for 241 cities, and found that the meteorological spring season of March through May has warmed by a national average of 2.4°F.
In an analysis released last month, the group found that 97% of the 241 cities analyzed saw a warming trend for the season.
Zoom in: Houston saw an increase of 4.1 degrees since 1970, and now has 24 more spring days with temperatures above normal, per Climate Central.
Between the lines: The spring warming in the U.S. is taking place in tandem with increasing temperatures around the world due to human emissions of greenhouse gases from burning fossil fuels such as coal, oil and gas.