How it works: The map above is ... slightly different from "first frost," which is related not just to temperature, but also to the amount of moisture in the air. The average first freeze date ...

The Frost and Freeze map shows where frost cant be expected and where temperature are forecast to fall below 32 degrees F. Frost is a solid deposition of water vapor from saturated air.

The big picture: The map above shows the average date of the first ... could arrive on Dec. 22. Context: First freeze is slightly different from "first frost," which is related to temperature ...