Frost dates for 55726Cromwell, MN
The average last spring frost in Cromwell is May 31 and the average first fall frost is September 18, giving a typical growing season of about 107 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 31
- Average first fall frost
- Sep 18
- Growing season
- 107 days
Safer after Jun 20 (1-in-10 risk)
Possible by Sep 1 (1-in-10 risk)
Last frost typically in 209 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) | — | — | 75 days | 100% |
| Frost / freeze (32°F) | May 15 · May 31 · Jun 20 | Sep 1 · Sep 18 · Oct 2 | 107 days | 100% |
| Hard freeze (28°F) | May 2 · May 17 · Jun 1 | Sep 13 · Sep 28 · Oct 13 | 133 days | 100% |
Planting calendar for Cromwell
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 30 – Jul 6 |
| Tomatoes | Transplant outdoors | Jun 16 – May 29 |
| Peppers | Start seeds indoors | Apr 30 – May 31 |
| Peppers | Transplant outdoors | Jun 30 – Jul 31 |
| Eggplant | Start seeds indoors | May 17 – Jun 15 |
| Eggplant | Transplant outdoors | Jun 30 – Jul 31 |
| Cucumbers | Sow outdoors | Jun 30 – Jun 8 |
| Summer squash | Sow outdoors | Jun 16 – Jul 31 |
| Winter squash & pumpkins | Sow outdoors | Jun 30 – Jul 31 |
| Snap beans | Sow outdoors | Jun 16 – Jul 1 |
| Sweet corn | Sow outdoors | Jun 16 – May 29 |
| Watermelon & cantaloupe | Sow outdoors | Jun 30 – Jul 31 |
| Okra | Sow outdoors | Jun 23 – Jul 16 |
| Peas | Sow outdoors (spring) | Apr 30 – Jun 15 |
| Potatoes | Plant outdoors (spring) | Apr 30 – Jun 30 |
| Onions | Start seeds indoors (spring) | Mar 19 – Apr 15 |
| Onions | Transplant outdoors (spring) | May 17 – Jun 15 |
| Broccoli | Start seeds indoors (spring) | Apr 12 – May 16 |
| Broccoli | Transplant outdoors (spring) | May 17 – Jun 15 |
| Broccoli | Start seeds indoors (fall) | May 19 – May 29 |
| Broccoli | Transplant outdoors (fall) | Jun 18 – Jun 29 |
| Cabbage | Start seeds indoors (spring) | Apr 2 – Apr 30 |
| Cabbage | Transplant outdoors (spring) | Apr 30 – May 31 |
| Cabbage | Start seeds indoors (fall) | May 9 – Jun 8 |
| Cabbage | Transplant outdoors (fall) | Jun 8 – Jul 9 |
| Leaf lettuce | Sow outdoors (spring) | Apr 30 – Jul 16 |
| Leaf lettuce | Sow outdoors (fall) | Jun 8 – Jul 25 |
| Spinach | Sow outdoors (spring) | Apr 23 – Jun 6 |
| Spinach | Sow outdoors (fall) | Jun 25 – Jul 30 |
| Radishes | Sow outdoors (spring) | Apr 30 – Jun 20 |
| Radishes | Sow outdoors (fall) | Jun 8 – Aug 9 |
| Kale | Sow outdoors (spring) | May 17 – Jun 6 |
| Kale | Sow outdoors (fall) | Jun 1 – Jul 9 |
| Carrots | Sow outdoors (spring) | May 31 – Jul 16 |
| Carrots | Sow outdoors (fall) | May 9 – Jun 24 |
| Garlic | Plant outdoors (fall) | Sep 8 – Oct 9 |
Where these dates come from
ZIP code 55726 is matched to the NOAA station Wright 3 E, MN, 6.2 km away, at 1,330 ft elevation (31 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Wright 3 E, MN (used) | 1,330 ft | May 31 | Sep 18 |
| Cloquet, MN | 1,265 ft | May 26 | Sep 23 |
| Moose Lake 1 Sse, MN | 1,110 ft | May 12 | Oct 2 |
| Floodwood 3 Ne, MN | 1,260 ft | May 29 | Sep 18 |
Frost dates near Cromwell
- Wright, MN 55798 · last May 31, first Sep 18
- Sawyer, MN 55780 · last May 26, first Sep 23
- Kettle River, MN 55757 · last May 12, first Oct 2
- Tamarack, MN 55787 · last May 31, first Sep 18
- Barnum, MN 55707 · last May 12, first Oct 2
- Brookston, MN 55711 · last May 26, first Sep 23
- Floodwood, MN 55736 · last May 29, first Sep 18
- Moose Lake, MN 55767 · last May 12, first Oct 2
Frequently asked questions
- When is the last frost in Cromwell, MN?
- For ZIP code 55726, the average last spring frost (32°F) is May 31, based on NOAA 1991-2020 climate normals for the Wright 3 E, MN weather station. There is a 1-in-10 chance of a frost after June 20.
- When is the first frost in Cromwell, MN?
- The average first fall frost (32°F) is September 18. There is a 1-in-10 chance of frost by September 1, so tender plants are at risk from that point on.
- How long is the growing season in 55726?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 107 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.