Frost dates for 56542Fosston, MN
The average last spring frost in Fosston is May 15 and the average first fall frost is September 26, giving a typical growing season of about 132 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 15
- Average first fall frost
- Sep 26
- Growing season
- 132 days
Safer after May 30 (1-in-10 risk)
Possible by Sep 10 (1-in-10 risk)
Last frost typically in 200 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 13 · May 27 · Jun 17 | Aug 28 · Sep 14 · Sep 28 | 109 days | 100% |
| Frost / freeze (32°F) | May 2 · May 15 · May 30 | Sep 10 · Sep 26 · Oct 8 | 132 days | 100% |
| Hard freeze (28°F) | Apr 20 · May 4 · May 20 | Sep 23 · Oct 5 · Oct 22 | 152 days | 100% |
Planting calendar for Fosston
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 14 – Jun 20 |
| Tomatoes | Transplant outdoors | May 31 – Jun 6 |
| Peppers | Start seeds indoors | Apr 14 – May 15 |
| Peppers | Transplant outdoors | Jun 14 – Jul 15 |
| Eggplant | Start seeds indoors | May 1 – May 30 |
| Eggplant | Transplant outdoors | Jun 14 – Jul 15 |
| Cucumbers | Sow outdoors | Jun 14 – Jun 16 |
| Summer squash | Sow outdoors | May 31 – Jul 15 |
| Winter squash & pumpkins | Sow outdoors | Jun 14 – Jul 15 |
| Snap beans | Sow outdoors | May 31 – Jul 9 |
| Sweet corn | Sow outdoors | May 31 – Jun 6 |
| Watermelon & cantaloupe | Sow outdoors | Jun 14 – Jul 15 |
| Okra | Sow outdoors | Jun 7 – Jun 30 |
| Peas | Sow outdoors (spring) | Apr 14 – May 30 |
| Potatoes | Plant outdoors (spring) | Apr 14 – Jun 14 |
| Onions | Start seeds indoors (spring) | Mar 3 – Mar 30 |
| Onions | Transplant outdoors (spring) | May 1 – May 30 |
| Broccoli | Start seeds indoors (spring) | Mar 27 – Apr 30 |
| Broccoli | Transplant outdoors (spring) | May 1 – May 30 |
| Broccoli | Start seeds indoors (fall) | May 27 – Jun 6 |
| Broccoli | Transplant outdoors (fall) | Jun 26 – Jul 7 |
| Cabbage | Start seeds indoors (spring) | Mar 17 – Apr 14 |
| Cabbage | Transplant outdoors (spring) | Apr 14 – May 15 |
| Cabbage | Start seeds indoors (fall) | May 17 – Jun 16 |
| Cabbage | Transplant outdoors (fall) | Jun 16 – Jul 17 |
| Leaf lettuce | Sow outdoors (spring) | Apr 14 – Jun 30 |
| Leaf lettuce | Sow outdoors (fall) | Jun 16 – Aug 2 |
| Spinach | Sow outdoors (spring) | Apr 7 – May 21 |
| Spinach | Sow outdoors (fall) | Jul 3 – Aug 7 |
| Radishes | Sow outdoors (spring) | Apr 14 – Jun 4 |
| Radishes | Sow outdoors (fall) | Jun 16 – Aug 17 |
| Kale | Sow outdoors (spring) | May 1 – May 21 |
| Kale | Sow outdoors (fall) | Jun 9 – Jul 17 |
| Carrots | Sow outdoors (spring) | May 15 – Jun 30 |
| Carrots | Sow outdoors (fall) | May 17 – Jul 2 |
| Garlic | Plant outdoors (fall) | Sep 16 – Oct 17 |
Where these dates come from
ZIP code 56542 is matched to the NOAA station Fosston 1 E, MN, 2.4 km away, at 1,300 ft elevation (3 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Fosston 1 E, MN (used) | 1,300 ft | May 15 | Sep 26 |
| Mahnomen, MN | 1,212 ft | May 7 | Sep 28 |
| Red Lake Falls, MN | 1,038 ft | May 9 | Sep 30 |
| Itasca Univ Of Minn, MN | 1,490 ft | May 18 | Sep 27 |
Frost dates near Fosston
- Lengby, MN 56651 · last May 15, first Sep 26
- Mcintosh, MN 56556 · last May 15, first Sep 26
- Trail, MN 56684 · last May 15, first Sep 26
- Winger, MN 56592 · last May 15, first Sep 26
- Bejou, MN 56516 · last May 7, first Sep 28
- Erskine, MN 56535 · last May 15, first Sep 26
- Gully, MN 56646 · last May 15, first Sep 26
- Gonvick, MN 56644 · last May 15, first Sep 26
Frequently asked questions
- When is the last frost in Fosston, MN?
- For ZIP code 56542, the average last spring frost (32°F) is May 15, based on NOAA 1991-2020 climate normals for the Fosston 1 E, MN weather station. There is a 1-in-10 chance of a frost after May 30.
- When is the first frost in Fosston, MN?
- The average first fall frost (32°F) is September 26. There is a 1-in-10 chance of frost by September 10, so tender plants are at risk from that point on.
- How long is the growing season in 56542?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 132 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.