Map of the contiguous United States showing regional observed increases in the frost-free season length

Observed changes in the length of the frost-free season by region. Click the image for more information.

The frost-free season is defined as the number of days between the last spring occurrence and the first fall occurrence of a minimum temperature at or below 32°F. This change is expressed as the change in the average number of frost-free days in 1986–2015 compared to 1901–1960. Figure source: updated from "Chapter 2: Our Changing Climate" in Climate Change Impacts in the United States: The Third National Climate Assessment, 2014.

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Last modified
13 December 2018 - 9:21am