Denver avoids extended allergy season
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Most major U.S. cities are suffering from longer allergy seasons amid human-caused climate change — but not Denver, a new analysis finds.
Driving the news: The freeze-free growing season lengthened between 1970 and 2024 in nearly 90% of the 198 cities analyzed by Climate Central, a research and communications group.
How it works: Climate Central uses the freeze-free period — the number of consecutive days with minimum temperatures above 32°F — as a proxy for allergy season.
- Above-freezing temperatures allow for better plant growth and thus the release of more sneeze-inducing pollen.
Yes, but: Denverites are getting a reprieve.
- The number of consecutive freeze-free days fell in Denver (-8) along with the Grand Junction area (-9). Meanwhile, those days in Colorado Springs grew (5).
Zoom in: Reno, Nevada (96); Myrtle Beach, South Carolina (52) and Toledo, Ohio (45) have had some of the biggest increases among cities analyzed.
Threat level: "Climate change makes pollen seasons not only longer, but also more intense due to heat-trapping pollution," per Climate Central's report.