When Is the Last Frost Date in My Zone?
Wondering when is the last frost date in your zone? Pick your USDA hardiness zone below and this free calculator instantly shows your estimated average last spring frost date, your average first fall frost date, and your growing season length in days. This tool finds your frost date; to plan seed-starting from it, use our Seed Starting Date Calculator.
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These are historical averages, not guarantees — in any year frost can arrive up to two weeks earlier or later. Always check your local 10-day forecast before setting out tender plants.
How to use this calculator
First, find your USDA hardiness zone. If you don't know it, search "USDA plant hardiness zone map" for your ZIP code, or check the back of any seed packet — zones run from 3 (very cold, like northern Minnesota) to 10 (very warm, like southern California).
Select your zone above. The calculator instantly shows three estimated dates for your zone: your average last spring frost (the date warm-season planting can begin), your average first fall frost (the end of the season), and the number of frost-free days between them — your growing season length.
Got your date? Plug it into our Seed Starting Date Calculator to plan exactly when to start each crop indoors.
How it works
USDA hardiness zones divide North America into bands based on the average annual minimum winter temperature, in 10°F steps. Zone 3 sees lows near −40°F to −30°F; Zone 10 rarely dips below 30°F. Because colder zones stay cold later into spring, their last frost date falls later — and warmer zones frost earlier.
The frost dates in this calculator are widely published approximate averages computed from decades of weather station records. They represent the long-term average last spring freeze, so in any given year the real date can shift earlier or later by a week or two. Your growing season length is simply the number of days between the average first fall frost and the average last spring frost, computed with calendar date math.
Average last frost dates by USDA zone (estimates):
| Zone | Last spring frost | First fall frost | Growing season |
|---|---|---|---|
| 3 | May 15 | Sep 10 | ≈ 118 days |
| 4 | May 1 | Sep 21 | ≈ 143 days |
| 5 | Apr 15 | Oct 1 | ≈ 169 days |
| 6 | Apr 1 | Oct 15 | ≈ 197 days |
| 7 | Mar 20 | Nov 15 | ≈ 240 days |
| 8 | Mar 1 | Nov 15 | ≈ 259 days |
| 9 | Feb 1 | Dec 1 | ≈ 303 days |
| 10 | Jan 15 | Dec 15 | ≈ 334 days |
Frequently asked questions
When is the last frost date in my zone?
The average last spring frost date depends on your USDA hardiness zone: about February 1 in Zone 9, March 20 in Zone 7, April 15 in Zone 5, and May 15 in Zone 3, with the other zones falling in between. Select your zone in the calculator above to see your average dates. Remember these are historical averages, not guarantees — in any given year frost can come up to two weeks earlier or later.
What is the last frost date based on?
Last frost dates are based on decades of recorded weather data. They are long-term averages — the date by which, on average, the last freezing temperature of spring has passed. Because they are averages, a late frost is always possible, so many gardeners wait one to two weeks past the average date before planting tender crops.
What can I plant before the last frost?
Cool-season crops tolerate light frost and can go in before the last frost date: peas, spinach, lettuce, kale, carrots, radishes, and onions. Warm-season crops like tomatoes, peppers, cucumbers, beans, squash, and basil should wait until after the last frost, when nights stay reliably above 50°F.
What if a frost is forecast after I already planted?
Cover tender plants with frost cloth, old bedsheets, or buckets in the evening, and water the soil during the day — moist soil holds warmth better than dry soil. Bring container plants indoors overnight. Remove covers in the morning so plants don't overheat. Most cool-season crops will shrug off a light frost on their own.
How is the last frost date different from the first frost date?
The last frost date is the average date of the final spring freeze, which tells you when to start warm-season planting. The first frost date is the average date of the first fall freeze, which tells you when the growing season ends. The days between them are your growing season — for example, about 240 days in Zone 7. The calculator above shows both.