Frost dates for 56431Aitkin, MN
The average last spring frost in Aitkin is May 16 and the average first fall frost is September 28, giving a typical growing season of about 133 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 16
- Average first fall frost
- Sep 28
- Growing season
- 133 days
Safer after Jun 1 (1-in-10 risk)
Possible by Sep 12 (1-in-10 risk)
Last frost typically in 194 days
Frost risk by date
NOAA reports frost dates as probabilities. The middle date is the average (a 50% chance). For spring, the 10% date is a safer planting date: frost after it happens in about 1 year in 10. Light frost (36°F) can damage tender plants; a hard freeze (28°F) kills most annuals.
| Temperature | Last spring: 90% / 50% / 10% chance | First fall: 10% / 50% / 90% chance | Growing season (50%) | Years with at least one |
|---|---|---|---|---|
| Light frost (36°F) | May 15 · May 28 · Jun 12 | Sep 2 · Sep 19 · Oct 1 | 112 days | 100% |
| Frost / freeze (32°F) | Apr 30 · May 16 · Jun 1 | Sep 12 · Sep 28 · Oct 12 | 133 days | 100% |
| Hard freeze (28°F) | Apr 19 · May 4 · May 21 | Sep 23 · Oct 8 · Oct 25 | 157 days | 100% |
Planting calendar for Aitkin
Planting windows from the University of Maryland Extension calendar, shifted to your average frost dates. Use them as a starting point and adjust for seed packet instructions and local conditions.
| Crop | Task | Window |
|---|---|---|
| Tomatoes | Start seeds indoors | Apr 15 – Jun 21 |
| Tomatoes | Transplant outdoors | Jun 1 – Jun 8 |
| Peppers | Start seeds indoors | Apr 15 – May 16 |
| Peppers | Transplant outdoors | Jun 15 – Jul 16 |
| Eggplant | Start seeds indoors | May 2 – May 31 |
| Eggplant | Transplant outdoors | Jun 15 – Jul 16 |
| Cucumbers | Sow outdoors | Jun 15 – Jun 18 |
| Summer squash | Sow outdoors | Jun 1 – Jul 16 |
| Winter squash & pumpkins | Sow outdoors | Jun 15 – Jul 16 |
| Snap beans | Sow outdoors | Jun 1 – Jul 11 |
| Sweet corn | Sow outdoors | Jun 1 – Jun 8 |
| Watermelon & cantaloupe | Sow outdoors | Jun 15 – Jul 16 |
| Okra | Sow outdoors | Jun 8 – Jul 1 |
| Peas | Sow outdoors (spring) | Apr 15 – May 31 |
| Potatoes | Plant outdoors (spring) | Apr 15 – Jun 15 |
| Onions | Start seeds indoors (spring) | Mar 4 – Mar 31 |
| Onions | Transplant outdoors (spring) | May 2 – May 31 |
| Broccoli | Start seeds indoors (spring) | Mar 28 – May 1 |
| Broccoli | Transplant outdoors (spring) | May 2 – May 31 |
| Broccoli | Start seeds indoors (fall) | May 29 – Jun 8 |
| Broccoli | Transplant outdoors (fall) | Jun 28 – Jul 9 |
| Cabbage | Start seeds indoors (spring) | Mar 18 – Apr 15 |
| Cabbage | Transplant outdoors (spring) | Apr 15 – May 16 |
| Cabbage | Start seeds indoors (fall) | May 19 – Jun 18 |
| Cabbage | Transplant outdoors (fall) | Jun 18 – Jul 19 |
| Leaf lettuce | Sow outdoors (spring) | Apr 15 – Jul 1 |
| Leaf lettuce | Sow outdoors (fall) | Jun 18 – Aug 4 |
| Spinach | Sow outdoors (spring) | Apr 8 – May 22 |
| Spinach | Sow outdoors (fall) | Jul 5 – Aug 9 |
| Radishes | Sow outdoors (spring) | Apr 15 – Jun 5 |
| Radishes | Sow outdoors (fall) | Jun 18 – Aug 19 |
| Kale | Sow outdoors (spring) | May 2 – May 22 |
| Kale | Sow outdoors (fall) | Jun 11 – Jul 19 |
| Carrots | Sow outdoors (spring) | May 16 – Jul 1 |
| Carrots | Sow outdoors (fall) | May 19 – Jul 4 |
| Garlic | Plant outdoors (fall) | Sep 18 – Oct 19 |
Where these dates come from
ZIP code 56431 is matched to the NOAA station Aitkin 2E, MN, 5.4 km away, at 1,215 ft elevation (42 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Aitkin 2E, MN (used) | 1,215 ft | May 16 | Sep 28 |
| Isle 12N, MN | 1,285 ft | May 10 | Oct 3 |
| Brainerd Crow Wing Co Ap, MN | 1,221 ft | May 13 | Sep 27 |
| Pine Rvr Dam, MN | 1,250 ft | May 6 | Oct 7 |
Frost dates near Aitkin
- Deerwood, MN 56444 · last May 16, first Sep 28
- Palisade, MN 56469 · last May 16, first Sep 28
- Ironton, MN 56455 · last May 13, first Sep 27
- Crosby, MN 56441 · last May 13, first Sep 27
- Mcgregor, MN 55760 · last May 7, first Oct 3
- Garrison, MN 56450 · last May 10, first Oct 3
- Isle, MN 56342 · last May 10, first Oct 3
- Mc Grath, MN 56350 · last May 10, first Oct 3
Frequently asked questions
- When is the last frost in Aitkin, MN?
- For ZIP code 56431, the average last spring frost (32°F) is May 16, based on NOAA 1991-2020 climate normals for the Aitkin 2E, MN weather station. There is a 1-in-10 chance of a frost after June 1.
- When is the first frost in Aitkin, MN?
- The average first fall frost (32°F) is September 28. There is a 1-in-10 chance of frost by September 12, so tender plants are at risk from that point on.
- How long is the growing season in 56431?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 133 days long.
- Are these frost dates a forecast?
- No. They are 30-year averages and probabilities from NOAA weather station records. Use them to plan, then watch your local forecast before planting tender crops or leaving them uncovered.