Fall Frost/Freeze Dates in Maryland

When will we see the first fall frost in Maryland?

This is one of the most commonly asked questions in September and October. The first frost will fluctuate from year to year and we cannot forecast an exact date it will occur. Historical temperature data provides the best guide to help predict this very important date.

To find your average first frost date, enter your location or zip code into the frost date app from The National Gardening Association: https://garden.org/apps/frost-dates/.

You will receive a chart like the example below:

The chart indicates a 10% chance that the temperature will go down to 32°F on October 13.  There is a 90% chance that it will be 32°F on November 15. The data is derived from the 1981–2010 U.S. Climate Normals from NOAA.

Two things to keep in mind:

1. The likelihood of frost will vary between landscapes in the same town or even neighborhood, due to many factors such as, changes in wind, elevation, and proximity to buildings and water;
   
   
2. The surest way to know when the first frost is expected is to closely monitor weather conditions using weather websites or your local news reports.

Why do gardeners care about the first frost? 

Very tender annual plants like basil, tomato, cucumber, pepper, zinnias, and marigolds are damaged or killed by freezing temperature. Plan to gather your final harvest before the first significant frost. Pumpkins, winter squash, white potatoes, and sweet potatoes can also be injured by a heavy frost. Cold temperatures will improve the flavor and texture of kale, collards, cabbage, and turnip greens. Bring tender houseplants and annual flowers like geraniums and begonias indoors before the first frost if you plan to keep them growing indoors through the winter.