Map: Observed Increase in Frost-Free Season Length

by
National Climate Assessment, NOAA NCDC / CICS-NC

The frost-free season length, defined as the period between the last occurrence of 32°F in the spring and the first occurrence of 32°F in the fall, has increased in each U.S. region during 1991-2012 relative to 1901-1960. Increases in frost-free season length correspond to similar increases in growing season length.