Frost dates for 55030Grasston, MN
The average last spring frost in Grasston is May 16 and the average first fall frost is September 24, giving a typical growing season of about 130 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 16
- Average first fall frost
- Sep 24
- Growing season
- 130 days
Safer after May 30 (1-in-10 risk)
Possible by Sep 9 (1-in-10 risk)
Last frost typically in 198 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 9 | Aug 31 · Sep 15 · Sep 29 | 111 days | 100% |
| Frost / freeze (32°F) | May 3 · May 16 · May 30 | Sep 9 · Sep 24 · Oct 6 | 130 days | 100% |
| Hard freeze (28°F) | Apr 21 · May 4 · May 20 | Sep 16 · Oct 2 · Oct 17 | 150 days | 100% |
Planting calendar for Grasston
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 4 |
| 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 14 |
| Summer squash | Sow outdoors | Jun 1 – Jul 16 |
| Winter squash & pumpkins | Sow outdoors | Jun 15 – Jul 16 |
| Snap beans | Sow outdoors | Jun 1 – Jul 7 |
| Sweet corn | Sow outdoors | Jun 1 – Jun 4 |
| 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 25 – Jun 4 |
| Broccoli | Transplant outdoors (fall) | Jun 24 – Jul 5 |
| Cabbage | Start seeds indoors (spring) | Mar 18 – Apr 15 |
| Cabbage | Transplant outdoors (spring) | Apr 15 – May 16 |
| Cabbage | Start seeds indoors (fall) | May 15 – Jun 14 |
| Cabbage | Transplant outdoors (fall) | Jun 14 – Jul 15 |
| Leaf lettuce | Sow outdoors (spring) | Apr 15 – Jul 1 |
| Leaf lettuce | Sow outdoors (fall) | Jun 14 – Jul 31 |
| Spinach | Sow outdoors (spring) | Apr 8 – May 22 |
| Spinach | Sow outdoors (fall) | Jul 1 – Aug 5 |
| Radishes | Sow outdoors (spring) | Apr 15 – Jun 5 |
| Radishes | Sow outdoors (fall) | Jun 14 – Aug 15 |
| Kale | Sow outdoors (spring) | May 2 – May 22 |
| Kale | Sow outdoors (fall) | Jun 7 – Jul 15 |
| Carrots | Sow outdoors (spring) | May 16 – Jul 1 |
| Carrots | Sow outdoors (fall) | May 15 – Jun 30 |
| Garlic | Plant outdoors (fall) | Sep 14 – Oct 15 |
Where these dates come from
ZIP code 55030 is matched to the NOAA station Hinckley, MN, 16.5 km away, at 1,035 ft elevation (51 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Hinckley, MN (used) | 1,035 ft | May 16 | Sep 24 |
| Mora, MN | 1,018 ft | May 9 | Sep 30 |
| Sandstone 6 W, MN | 1,130 ft | May 13 | Sep 29 |
| Grantsburg, WI | 990 ft | May 11 | Oct 1 |
Frost dates near Grasston
- Henriette, MN 55036 · last May 9, first Sep 30
- Brook Park, MN 55007 · last May 16, first Sep 24
- Pine City, MN 55063 · last May 11, first Oct 1
- Rock Creek, MN 55067 · last May 11, first Oct 1
- Mora, MN 55051 · last May 9, first Sep 30
- Braham, MN 55006 · last May 2, first Oct 4
- Rush City, MN 55069 · last May 11, first Oct 1
- Hinckley, MN 55037 · last May 16, first Sep 24
Frequently asked questions
- When is the last frost in Grasston, MN?
- For ZIP code 55030, the average last spring frost (32°F) is May 16, based on NOAA 1991-2020 climate normals for the Hinckley, MN weather station. There is a 1-in-10 chance of a frost after May 30.
- When is the first frost in Grasston, MN?
- The average first fall frost (32°F) is September 24. There is a 1-in-10 chance of frost by September 9, so tender plants are at risk from that point on.
- How long is the growing season in 55030?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 130 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.