Warming October nights & Halloween extremes

KEY CONCEPTS

• Fall temperatures have warmed by 2.7°F on average across the U.S. since 1970. 

• Fall warming can extend allergy and mosquito seasons, and disrupt leaf-peeping. 

• Warming trends have also taken the chill out of another fall tradition: trick-or-treating. 

• Since 1970, October nights have warmed by 2.2°F on average across the U.S. 

• 89% of 247 locations analyzed experienced warming on October nights. 

• About two-thirds of locations have warmed by more than 2°F since 1970.

• Graphics show local warming trends and Halloween extremes for 247 U.S. locations.

METHODOLOGY:

October minimum temperatures from 1970-2021 were retrieved from the Applied Climate Information System (ACIS). Local Halloween climate extremes were also retrieved from ACIS, but included each station’s entire period of record. Climate Central's local analyses include 247 stations. However, for data summaries based on linear trends, only 246 stations are included due to large data gaps in Wheeling, W. Va.