Scientists have found that human activity is causing spring to get warmer in almost every major U.S. city. They looked at 241 cities from 1970 to 2025 and discovered that 98% of them are experiencing warmer springs because of climate change.
Spring temperatures have risen by an average of 2.6 degrees Fahrenheit. Cities in the Southwest, South, and Southeast have warmed the most. Reno, Nevada had the biggest change, warming by almost 7 degrees.
Most cities now have at least seven extra warm spring days compared to the 1970s. El Paso, Texas has 39 more warm spring days than before.
Warmer springs cause problems. Allergy season lasts longer because plants release pollen earlier and later in the year. Wildfire risk increases in dry areas. Mountain snow melts earlier, which means less water for farms and cities in summer. Disease-carrying mosquitoes also survive longer when winters and springs are warmer.
Human activities like burning fossil fuels for cars and electricity create pollution that traps heat and causes these temperature changes.