Warmer Fall, Later Freeze

Climate Central's analysis of 200 U.S. cities shows that the first fall freeze is arriving later in 85% of locations, delaying the date by an average of 11 days since 1970. This trend, alongside a 2.4°F average increase in fall temperatures across the contiguous U.S., extends growing seasons and disrupts ecological cues, leading to prolonged allergy seasons, lingering pests, and reduced yields for the U.S. fruit and nut industry.

• Since 1970, the first fall freeze (the first day with minimum temperatures at or below 32°F) has arrived later in 170 of the 200 analyzed U.S. cities, representing 85% of the sample. In these cities, the freeze is arriving 11 days later on average than in the early 1970s.
• The delay in the first freeze is most pronounced in 57 cities, particularly those in the Upper Midwest and Northeast, where the freeze now arrives at least two weeks later. The most significant shifts since 1970 occurred in Reno, Nev. (41 days later), Bend, Ore. (37 days later), Toledo, Ohio (28 days later), Boise, Idaho (27 days later), Manchester, N.H. (27 days later), and Helena, Mont. (26 days later).
• The contiguous U.S. has experienced an average fall temperature increase of 2.4°F since 1970. This warming, combined with earlier spring thaws, has extended the annual freeze-free season in 164 U.S. cities since 1970.
• Delayed fall freezes and longer growing seasons have several negative impacts: they extend the ragweed pollen season, allow disease-carrying insects like mosquitoes to survive longer, and disrupt the chilling periods required for high-quality non-citrus fruit and nut yields, which is a nearly $27 billion U.S. industry.

APA

Climate Central (2024). Warmer Fall, Later Freeze. https://www.climatecentral.org/climate-matters/warmer-fall-later-freeze

Chicago

Climate Central. Warmer Fall, Later Freeze. 2024. https://www.climatecentral.org/climate-matters/warmer-fall-later-freeze.

Wikipedia

{{cite report |author=Climate Central |title=Warmer Fall, Later Freeze |date=16 October 2024 |url=https://www.climatecentral.org/climate-matters/warmer-fall-later-freeze |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{climatecentral2024warmer, author = {{Climate Central}}, title = {{Warmer Fall, Later Freeze}}, institution = {Climate Central}, year = {2024}, month = oct, url = {https://www.climatecentral.org/climate-matters/warmer-fall-later-freeze}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }