When will we see the first fall frost in Maryland?
To find your average first frost date, these are two resources we recommend:
- Purdue University's Freeze Date Tool. Select your county on the map to get your average first frost date.
- The National Gardening Association's Frost Dates by Zip Code.
From The National Gardening Association page, you will receive a chart like in the example below:
| Frederick, MD | 10% | 30% | 50% | 70% | 90% |
| First 32°F | Oct 13 | Oct 23 | Oct 30 | Nov 5 | Nov 15 |
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 1991–2020 U.S. Climate Normals from NOAA.
Two things to keep in mind:
- 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;
- 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 indoor plants and annual flowers like geraniums and begonias indoors before the first frost if you plan to keep them growing indoors through the winter.