A freeze warning is issued when the nighttime low temperatures across the whole county or forecast zone are predicted to be at or below 32 degrees.
A freeze warning is issued when low temperatures are expected to be 29 to 32 degrees, and a hard freeze warning is issued when temperatures are expected to be 28 degrees or less.
A frost, freeze or hard freeze watch may be issued a few days ahead of time if the potential exists for temperatures to fall into the appropriate thresholds.
The National Weather Service, or NWS, officially issues all weather warnings and watches. Those include frost, freeze and hard freeze watches and warnings. The NWS issues these types of watches and warnings after the beginning and before the end of the growing season. A watch or warning can be extended beyond that time if necessary.
The NWS issues these warnings as cold temperatures can damage plants and impact agriculture, nurseries and home gardening. The beginning of the growing season is set by the average date of the last freeze in spring. The end of the growing season is the average date of the first freeze in autumn.
The Midwest Regional Climate Center has maps that show the first and last days of the year for a freeze at go.madison.com/freeze.