A page from the garden notebook
Frost Dates: How to Find Your First and Last Frost Date
Frost dates explained: what last spring and first fall frost dates mean, why they are uncertain, and how to use them safely.
By David Choi · Updated · How we source and review advice
A frost date is a planning estimate from past weather. It is not a promise that frost will stop or start on one exact day. Use it to plan, then use the current forecast to protect real plants.
The two dates gardeners use
- The last spring frost is the approximate end of spring frost risk.
- The first fall frost is the approximate start of fall frost risk.
- The time between them is the approximate frost-free growing season.
Why the date can be wrong for your garden
Climate normals describe typical conditions across many years. Your garden may sit higher, lower, nearer water, beside pavement, against a wall, or in a windy opening. These local features create a microclimate that can be warmer or colder than the nearby weather station.
Frost can form near plants even when the official air temperature is slightly above freezing. Clear skies, light wind, and low or sheltered ground can increase the risk.
A freeze and a killing frost are not the same promise
A forecast near 32°F is a clear warning, but plant damage depends on the crop, exposure time, wind, humidity, and the temperature at leaf level. There is no single killing-frost temperature that describes every plant.
Use the spring date
Use the last spring frost to estimate when tender crops may move outside. Then check the crop's cold tolerance, soil temperature, recent weather, and short-range forecast. Cold-tolerant crops may go out earlier. Warm-season crops often need warmer soil and nights.
Use the fall date
Use the first fall frost to judge whether a crop has enough time left to mature and whether tender plants may need protection or harvest. Leave room for slower growth as days cool instead of planting on the last possible date.
When frost is in the forecast
- Check which crops are frost-sensitive.
- Harvest tender food that is ready.
- Cover tender plants before evening when suitable for that crop.
- Remove the cover after temperatures rise.
- Use the forecast again the next night.
Sources
- U.S. Climate Normals (NOAA National Centers for Environmental Information)
- Frost Dates (University of Wisconsin-Madison Extension)
- Frost (National Weather Service)
Start with your region
These state guides offer broad crop choices. Save your ZIP for local planting times.
Crops in this guide
Tomato
A warm season fruit that almost everyone treats as a vegetable, and the crop most people try first. It needs heat, steady water and something to lean on.
- Harvest
- 50 to 85 daysfrom transplant
- Effort
- Season
- Warm
Basil
A tender summer herb that grows fast, hates cold nights, and gives more the more often you cut it.
- Harvest
- 50 to 75 days
- Effort
- Season
- Warm
Lettuce
A fast, cool weather leaf crop that you can pick from for weeks. It is at its best in spring and autumn, and turns bitter in a hot, dry spell.
- Harvest
- 50 to 70 days
- Effort
- Season
- Cool
Carrot
A root crop that asks for little except loose, stone free ground and patience while it germinates.
- Harvest
- 70 to 80 days
- Effort
- Season
- Cool
Strawberry
A low perennial that fruits for years once established. The first summer is about getting the plants settled; the real crop comes after that.
- Harvest
- 300 to 400 daysfrom transplant
- Effort
- Season
- Cool
Your next useful step
- Vegetable Planting Calendar by ZIP Code
A vegetable planting calendar by ZIP code with month-by-month planting, growing and harvest actions from your usual frost dates.
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How to start seeds indoors with a simple routine, from choosing crops to moving sturdy seedlings outside.
- How to Grow Your Own Food
A realistic way to turn the space and time you have into useful harvests across the season.