Frost dates for 55604Grand Marais, MN
The average last spring frost in Grand Marais is May 26 and the average first fall frost is September 27, giving a typical growing season of about 126 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 26
- Average first fall frost
- Sep 27
- Growing season
- 126 days
Safer after Jun 6 (1-in-10 risk)
Possible by Sep 13 (1-in-10 risk)
Last frost typically in 205 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 23 · Jun 4 · Jun 19 | Sep 2 · Sep 16 · Sep 29 | 104 days | 100% |
| Frost / freeze (32°F) | May 9 · May 26 · Jun 6 | Sep 13 · Sep 27 · Oct 9 | 126 days | 100% |
| Hard freeze (28°F) | Apr 29 · May 10 · May 26 | Sep 24 · Oct 7 · Oct 21 | 148 days | 100% |
Planting calendar for Grand Marais
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 25 – Jul 1 |
| Tomatoes | Transplant outdoors | Jun 11 – Jun 7 |
| Peppers | Start seeds indoors | Apr 25 – May 26 |
| Peppers | Transplant outdoors | Jun 25 – Jul 26 |
| Eggplant | Start seeds indoors | May 12 – Jun 10 |
| Eggplant | Transplant outdoors | Jun 25 – Jul 26 |
| Cucumbers | Sow outdoors | Jun 25 – Jun 17 |
| Summer squash | Sow outdoors | Jun 11 – Jul 26 |
| Winter squash & pumpkins | Sow outdoors | Jun 25 – Jul 26 |
| Snap beans | Sow outdoors | Jun 11 – Jul 10 |
| Sweet corn | Sow outdoors | Jun 11 – Jun 7 |
| Watermelon & cantaloupe | Sow outdoors | Jun 25 – Jul 26 |
| Okra | Sow outdoors | Jun 18 – Jul 11 |
| Peas | Sow outdoors (spring) | Apr 25 – Jun 10 |
| Potatoes | Plant outdoors (spring) | Apr 25 – Jun 25 |
| Onions | Start seeds indoors (spring) | Mar 14 – Apr 10 |
| Onions | Transplant outdoors (spring) | May 12 – Jun 10 |
| Broccoli | Start seeds indoors (spring) | Apr 7 – May 11 |
| Broccoli | Transplant outdoors (spring) | May 12 – Jun 10 |
| Broccoli | Start seeds indoors (fall) | May 28 – Jun 7 |
| Broccoli | Transplant outdoors (fall) | Jun 27 – Jul 8 |
| Cabbage | Start seeds indoors (spring) | Mar 28 – Apr 25 |
| Cabbage | Transplant outdoors (spring) | Apr 25 – May 26 |
| Cabbage | Start seeds indoors (fall) | May 18 – Jun 17 |
| Cabbage | Transplant outdoors (fall) | Jun 17 – Jul 18 |
| Leaf lettuce | Sow outdoors (spring) | Apr 25 – Jul 11 |
| Leaf lettuce | Sow outdoors (fall) | Jun 17 – Aug 3 |
| Spinach | Sow outdoors (spring) | Apr 18 – Jun 1 |
| Spinach | Sow outdoors (fall) | Jul 4 – Aug 8 |
| Radishes | Sow outdoors (spring) | Apr 25 – Jun 15 |
| Radishes | Sow outdoors (fall) | Jun 17 – Aug 18 |
| Kale | Sow outdoors (spring) | May 12 – Jun 1 |
| Kale | Sow outdoors (fall) | Jun 10 – Jul 18 |
| Carrots | Sow outdoors (spring) | May 26 – Jul 11 |
| Carrots | Sow outdoors (fall) | May 18 – Jul 3 |
| Garlic | Plant outdoors (fall) | Sep 17 – Oct 18 |
Where these dates come from
ZIP code 55604 is matched to the NOAA station Lutsen 3Nne, MN, 25.9 km away, at 1,300 ft elevation (213 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Lutsen 3Nne, MN (used) | 1,300 ft | May 26 | Sep 27 |
| Grand Marais, MN | 612 ft | May 20 | Oct 5 |
| Grand Marais, MN | 610 ft | May 22 | Oct 9 |
| Grand Portage, MN | 730 ft | May 24 | Sep 29 |
Frost dates near Grand Marais
- Hovland, MN 55606 · last May 20, first Oct 5
- Lutsen, MN 55612 · last May 26, first Sep 27
- Tofte, MN 55615 · last May 22, first Oct 9
- Schroeder, MN 55613 · last May 26, first Sep 27
- Grand Portage, MN 55605 · last May 24, first Sep 29
- Finland, MN 55603 · last May 15, first Oct 1
- Silver Bay, MN 55614 · last May 15, first Oct 1
- Isabella, MN 55607 · last May 31, first Sep 15
Frequently asked questions
- When is the last frost in Grand Marais, MN?
- For ZIP code 55604, the average last spring frost (32°F) is May 26, based on NOAA 1991-2020 climate normals for the Lutsen 3Nne, MN weather station. There is a 1-in-10 chance of a frost after June 6.
- When is the first frost in Grand Marais, MN?
- The average first fall frost (32°F) is September 27. There is a 1-in-10 chance of frost by September 13, so tender plants are at risk from that point on.
- How long is the growing season in 55604?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 126 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.