Frost dates for 48468Port Hope, MI
The average last spring frost in Port Hope is May 5 and the average first fall frost is October 24, giving a typical growing season of about 169 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 5
- Average first fall frost
- Oct 24
- Growing season
- 169 days
Safer after May 21 (1-in-10 risk)
Possible by Oct 7 (1-in-10 risk)
Last frost typically in 184 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 2 · May 18 · May 31 | Sep 26 · Oct 10 · Oct 25 | 145 days | 100% |
| Frost / freeze (32°F) | Apr 21 · May 5 · May 21 | Oct 7 · Oct 24 · Nov 5 | 169 days | 100% |
| Hard freeze (28°F) | Apr 8 · Apr 21 · May 7 | Oct 21 · Nov 5 · Nov 19 | 194 days | 100% |
Planting calendar for Port Hope
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 4 – Jun 10 |
| Tomatoes | Transplant outdoors | May 21 – Jul 4 |
| Peppers | Start seeds indoors | Apr 4 – May 5 |
| Peppers | Transplant outdoors | Jun 4 – Jul 5 |
| Eggplant | Start seeds indoors | Apr 21 – May 20 |
| Eggplant | Transplant outdoors | Jun 4 – Jul 5 |
| Cucumbers | Sow outdoors | Jun 4 – Jul 14 |
| Summer squash | Sow outdoors | May 21 – Jul 5 |
| Winter squash & pumpkins | Sow outdoors | Jun 4 – Jul 5 |
| Snap beans | Sow outdoors | May 21 – Aug 6 |
| Sweet corn | Sow outdoors | May 21 – Jul 4 |
| Watermelon & cantaloupe | Sow outdoors | Jun 4 – Jul 5 |
| Okra | Sow outdoors | May 28 – Jun 20 |
| Peas | Sow outdoors (spring) | Apr 4 – May 20 |
| Potatoes | Plant outdoors (spring) | Apr 4 – Jun 4 |
| Onions | Start seeds indoors (spring) | Feb 21 – Mar 20 |
| Onions | Transplant outdoors (spring) | Apr 21 – May 20 |
| Broccoli | Start seeds indoors (spring) | Mar 17 – Apr 20 |
| Broccoli | Transplant outdoors (spring) | Apr 21 – May 20 |
| Broccoli | Start seeds indoors (fall) | Jun 24 – Jul 4 |
| Broccoli | Transplant outdoors (fall) | Jul 24 – Aug 4 |
| Cabbage | Start seeds indoors (spring) | Mar 7 – Apr 4 |
| Cabbage | Transplant outdoors (spring) | Apr 4 – May 5 |
| Cabbage | Start seeds indoors (fall) | Jun 14 – Jul 14 |
| Cabbage | Transplant outdoors (fall) | Jul 14 – Aug 14 |
| Leaf lettuce | Sow outdoors (spring) | Apr 4 – Jun 20 |
| Leaf lettuce | Sow outdoors (fall) | Jul 14 – Aug 30 |
| Spinach | Sow outdoors (spring) | Mar 28 – May 11 |
| Spinach | Sow outdoors (fall) | Jul 31 – Sep 4 |
| Radishes | Sow outdoors (spring) | Apr 4 – May 25 |
| Radishes | Sow outdoors (fall) | Jul 14 – Sep 14 |
| Kale | Sow outdoors (spring) | Apr 21 – May 11 |
| Kale | Sow outdoors (fall) | Jul 7 – Aug 14 |
| Carrots | Sow outdoors (spring) | May 5 – Jun 20 |
| Carrots | Sow outdoors (fall) | Jun 14 – Jul 30 |
| Garlic | Plant outdoors (fall) | Oct 14 – Nov 14 |
Where these dates come from
ZIP code 48468 is matched to the NOAA station Port Hope, MI, 3.8 km away, at 600 ft elevation (76 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Port Hope, MI (used) | 600 ft | May 5 | Oct 24 |
| Port Hope, MI | 590 ft | Apr 28 | Nov 3 |
| Harbor Beach 1 Sse, MI | 595 ft | May 2 | Oct 24 |
| Port Austin Wwtp, MI | 605 ft | May 4 | Oct 26 |
Frost dates near Port Hope
- Harbor Beach, MI 48441 · last May 2, first Oct 24
- Kinde, MI 48445 · last May 8, first Oct 17
- Filion, MI 48432 · last May 5, first Oct 19
- Ruth, MI 48470 · last May 2, first Oct 24
- Port Austin, MI 48467 · last May 8, first Oct 17
- Bad Axe, MI 48413 · last May 5, first Oct 19
- Minden City, MI 48456 · last May 2, first Oct 24
- Ubly, MI 48475 · last May 5, first Oct 19
Frequently asked questions
- When is the last frost in Port Hope, MI?
- For ZIP code 48468, the average last spring frost (32°F) is May 5, based on NOAA 1991-2020 climate normals for the Port Hope, MI weather station. There is a 1-in-10 chance of a frost after May 21.
- When is the first frost in Port Hope, 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 48468?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 169 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.