Frost calendar — 2026
Frost dates for USDA Zone 3
Last spring & first fall frost · Northern Minnesota, North Dakota, interior Alaska · 110-day growing season
Zone 3 frost-date table
| Average last spring frost | late May |
|---|---|
| Average first fall frost | early September |
| Frost-free growing days | ~110 days |
| Average annual minimum temperature | -40 to -30°F (-40 to -34°C) |
| Typical regions | Northern Minnesota, North Dakota, interior Alaska |
Frost-date averages: NOAA Climate Data Online national averages within USDA Zone 3. Local ZIP-code-precise dates can vary by one to three weeks from these zone midpoints.
What the frost dates mean for planting in Zone 3
The last spring frost is your green light for tender crops; the first fall frost is the deadline that ends the warm-season harvest. Frost-tender vegetables need row covers and short-season varieties. Heat-loving crops (peppers, eggplant) require greenhouses or season extension.
Tender crops to sow after Zone 3's last frost
- When to plant tomatoes in Zone 3 — sow about 10 days after the last frost.
- When to plant basil in Zone 3 — sow about 7 days after the last frost.
- When to plant bush beans in Zone 3 — sow about 10 days after the last frost.
- When to plant cucumbers in Zone 3 — sow about 14 days after the last frost.
- When to plant summer squash in Zone 3 — sow about 14 days after the last frost.
Hardy crops (peas, lettuce, carrots) can go in two to five weeks before the last spring frost — they tolerate light cold that would kill the tender list above.
How to use these dates
- Anchor your spring planting to the last frost. Count backwards to start seeds indoors, and forward to time transplanting tender crops outside.
- Anchor your fall wind-down to the first frost. Stop sowing anything that cannot mature before that date, and start harvesting or covering tender crops two weeks ahead.
- Adjust for your microclimate. A south-facing wall, urban heat, or a frost pocket shifts these zone averages by one to three weeks — track your own first and last frosts each year.
- Get a ZIP-precise estimate. Run the frost-date calculator for dates closer to your exact location.
Want exact frost dates for your address?
These are Zone 3 averages. Growli pins your frost dates to your ZIP code or postcode and sends a push notification 24–48 hours before any forecast frost night for your saved location.
Frequently asked questions
When is the last spring frost in USDA Zone 3?
The average last spring frost in USDA Zone 3 falls around late May. This is a 30-year national average within the zone; your specific yard can run one to two weeks earlier or later depending on microclimate.
When is the first fall frost in USDA Zone 3?
The average first fall frost in USDA Zone 3 arrives around early September. Start watching the 10-day forecast about two weeks before that date and have row covers ready for tender crops.
How long is the growing season in Zone 3?
USDA Zone 3 has roughly 110 frost-free growing days between the average last spring frost and the average first fall frost. Cold-hardy fruit trees plus most cool-season vegetables.
What can I plant after the last frost in Zone 3?
Tender warm-season crops go out once Zone 3's last frost has passed: tomatoes, basil, bush beans, cucumbers, summer squash. Hardy crops like peas, lettuce, and carrots can go in weeks before the last frost.
Are these frost dates exact for my address?
No — these are zone-wide 30-year averages from NOAA Climate Data Online. Local microclimates (south-facing slopes, urban heat, frost pockets, lakeside warmth) can shift your real dates by one to three weeks. Use the Growli frost-date calculator with your ZIP code for a closer estimate.