Frost dates for 48441Harbor Beach, MI
The average last spring frost in Harbor Beach is May 2 and the average first fall frost is October 24, giving a typical growing season of about 173 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 2
- Average first fall frost
- Oct 24
- Growing season
- 173 days
Safer after May 17 (1-in-10 risk)
Possible by Oct 7 (1-in-10 risk)
Last frost typically in 181 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 1 · May 15 · May 28 | Sep 29 · Oct 11 · Oct 24 | 148 days | 100% |
| Frost / freeze (32°F) | Apr 19 · May 2 · May 17 | Oct 7 · Oct 24 · Nov 6 | 173 days | 100% |
| Hard freeze (28°F) | Apr 7 · Apr 20 · May 4 | Oct 21 · Nov 3 · Nov 18 | 198 days | 100% |
Planting calendar for Harbor Beach
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 1 – Jun 7 |
| Tomatoes | Transplant outdoors | May 18 – Jul 4 |
| Peppers | Start seeds indoors | Apr 1 – May 2 |
| Peppers | Transplant outdoors | Jun 1 – Jul 2 |
| Eggplant | Start seeds indoors | Apr 18 – May 17 |
| Eggplant | Transplant outdoors | Jun 1 – Jul 2 |
| Cucumbers | Sow outdoors | Jun 1 – Jul 14 |
| Summer squash | Sow outdoors | May 18 – Jul 2 |
| Winter squash & pumpkins | Sow outdoors | Jun 1 – Jul 2 |
| Snap beans | Sow outdoors | May 18 – Aug 6 |
| Sweet corn | Sow outdoors | May 18 – Jul 4 |
| Watermelon & cantaloupe | Sow outdoors | Jun 1 – Jul 2 |
| Okra | Sow outdoors | May 25 – Jun 17 |
| Peas | Sow outdoors (spring) | Apr 1 – May 17 |
| Potatoes | Plant outdoors (spring) | Apr 1 – Jun 1 |
| Onions | Start seeds indoors (spring) | Feb 18 – Mar 17 |
| Onions | Transplant outdoors (spring) | Apr 18 – May 17 |
| Broccoli | Start seeds indoors (spring) | Mar 14 – Apr 17 |
| Broccoli | Transplant outdoors (spring) | Apr 18 – May 17 |
| Broccoli | Start seeds indoors (fall) | Jun 24 – Jul 4 |
| Broccoli | Transplant outdoors (fall) | Jul 24 – Aug 4 |
| Cabbage | Start seeds indoors (spring) | Mar 4 – Apr 1 |
| Cabbage | Transplant outdoors (spring) | Apr 1 – May 2 |
| Cabbage | Start seeds indoors (fall) | Jun 14 – Jul 14 |
| Cabbage | Transplant outdoors (fall) | Jul 14 – Aug 14 |
| Leaf lettuce | Sow outdoors (spring) | Apr 1 – Jun 17 |
| Leaf lettuce | Sow outdoors (fall) | Jul 14 – Aug 30 |
| Spinach | Sow outdoors (spring) | Mar 25 – May 8 |
| Spinach | Sow outdoors (fall) | Jul 31 – Sep 4 |
| Radishes | Sow outdoors (spring) | Apr 1 – May 22 |
| Radishes | Sow outdoors (fall) | Jul 14 – Sep 14 |
| Kale | Sow outdoors (spring) | Apr 18 – May 8 |
| Kale | Sow outdoors (fall) | Jul 7 – Aug 14 |
| Carrots | Sow outdoors (spring) | May 2 – Jun 17 |
| Carrots | Sow outdoors (fall) | Jun 14 – Jul 30 |
| Garlic | Plant outdoors (fall) | Oct 14 – Nov 14 |
Where these dates come from
ZIP code 48441 is matched to the NOAA station Harbor Beach 1 Sse, MI, 3.7 km away, at 595 ft elevation (84 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Harbor Beach 1 Sse, MI (used) | 595 ft | May 2 | Oct 24 |
| Port Hope, MI | 600 ft | May 5 | Oct 24 |
| Port Hope, MI | 590 ft | Apr 28 | Nov 3 |
| Bad Axe, MI | 715 ft | May 5 | Oct 19 |
Frost dates near Harbor Beach
- Ruth, MI 48470 · last May 2, first Oct 24
- Port Hope, MI 48468 · last May 5, first Oct 24
- Minden City, MI 48456 · last May 2, first Oct 24
- Forestville, MI 48434 · last May 2, first Oct 24
- Palms, MI 48465 · last May 2, first Oct 16
- Filion, MI 48432 · last May 5, first Oct 19
- Bad Axe, MI 48413 · last May 5, first Oct 19
- Kinde, MI 48445 · last May 8, first Oct 17
Frequently asked questions
- When is the last frost in Harbor Beach, MI?
- For ZIP code 48441, the average last spring frost (32°F) is May 2, based on NOAA 1991-2020 climate normals for the Harbor Beach 1 Sse, MI weather station. There is a 1-in-10 chance of a frost after May 17.
- When is the first frost in Harbor Beach, MI?
- The average first fall frost (32°F) is October 24. There is a 1-in-10 chance of frost by October 7, so tender plants are at risk from that point on.
- How long is the growing season in 48441?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 173 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.