National Weather Service United States Department of Commerce

...NWS Gray will conduct an experiment this fall to improve services related to the Frost/Freeze Program...  

The National Weather Service’s (NWS) Frost/Freeze Program consists of issuing Frost Advisories, Freeze Warnings or Hard Freeze Warnings when cold temperatures threaten tender vegetation and crops during the climatological growing season. The growing season is defined by the period of time between the median date of the last Spring Freeze and the median date of the first Fall Freeze. 
Currently, the ending of the issuance of Frost/Freeze headlines for a season in a weather forecast zone is based on the occurrence of a freeze, or two weeks after the median first Fall Freeze date when no freeze occurs. This approach was confusing to many users as meteorological conditions often led to a patchwork approach of ending the growing season across multiple weather forecast zones and NWS offices.
The Northern New England NWS forecast offices (Burlington VT/Caribou ME/Albany NY) and the NWS Gray ME office will conduct an experimental program service during the fall of 2021. The purpose of this experimental program is to streamline the Frost/Freeze program for simplified customer usability.  
The end of the seasonal Frost/Freeze program will be determined by the climatological median first Fall Freeze date. This means that these NWS offices will use a fixed date for the climatologically defined areas, based on 30-Year temperature averages, to end the growing season. 
During the defined growing season, NWS Gray will issue frost/freeze headlines as needed. Once the end date of the climatologically defined growing season is reached, frost/freeze headlines will no longer be issued for that climatological area as frost and freeze are expected. 
The following are the climatologically defined areas and their respective ending dates of the growing season in New Hampshire and western Maine:


Frost / Freeze End Date

Coos County NH & Western Maine Mountains September 21st
Maine Foothills, White Mountains, CT River Valley, Monadnock Region, NH Lakes Region and Merrimack River Valley October 1st
NH Seacoast, Maine Midcoast, York, Cumberland, Androscoggin & Kennebec Counties October 11th

If you have any questions or comments on this experiment, please reach out to Donald Dumont, Warning Coordination Meteorologist at or call 207-688-3216.

NWS Gray Frost/Freeze Program