Frost dates for 49701Mackinaw City, MI
The average last spring frost in Mackinaw City is May 7 and the average first fall frost is October 23, giving a typical growing season of about 167 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 7
- Average first fall frost
- Oct 23
- Growing season
- 167 days
Safer after May 22 (1-in-10 risk)
Possible by Oct 6 (1-in-10 risk)
Last frost typically in 186 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 6 · May 20 · Jun 2 | Sep 28 · Oct 9 · Oct 25 | 142 days | 100% |
| Frost / freeze (32°F) | Apr 25 · May 7 · May 22 | Oct 6 · Oct 23 · Nov 6 | 167 days | 100% |
| Hard freeze (28°F) | Apr 11 · Apr 25 · May 10 | Oct 21 · Nov 3 · Nov 18 | 191 days | 100% |
Planting calendar for Mackinaw City
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 6 – Jun 12 |
| Tomatoes | Transplant outdoors | May 23 – Jul 3 |
| Peppers | Start seeds indoors | Apr 6 – May 7 |
| Peppers | Transplant outdoors | Jun 6 – Jul 7 |
| Eggplant | Start seeds indoors | Apr 23 – May 22 |
| Eggplant | Transplant outdoors | Jun 6 – Jul 7 |
| Cucumbers | Sow outdoors | Jun 6 – Jul 13 |
| Summer squash | Sow outdoors | May 23 – Jul 7 |
| Winter squash & pumpkins | Sow outdoors | Jun 6 – Jul 7 |
| Snap beans | Sow outdoors | May 23 – Aug 5 |
| Sweet corn | Sow outdoors | May 23 – Jul 3 |
| Watermelon & cantaloupe | Sow outdoors | Jun 6 – Jul 7 |
| Okra | Sow outdoors | May 30 – Jun 22 |
| Peas | Sow outdoors (spring) | Apr 6 – May 22 |
| Potatoes | Plant outdoors (spring) | Apr 6 – Jun 6 |
| Onions | Start seeds indoors (spring) | Feb 23 – Mar 22 |
| Onions | Transplant outdoors (spring) | Apr 23 – May 22 |
| Broccoli | Start seeds indoors (spring) | Mar 19 – Apr 22 |
| Broccoli | Transplant outdoors (spring) | Apr 23 – May 22 |
| Broccoli | Start seeds indoors (fall) | Jun 23 – Jul 3 |
| Broccoli | Transplant outdoors (fall) | Jul 23 – Aug 3 |
| Cabbage | Start seeds indoors (spring) | Mar 9 – Apr 6 |
| Cabbage | Transplant outdoors (spring) | Apr 6 – May 7 |
| Cabbage | Start seeds indoors (fall) | Jun 13 – Jul 13 |
| Cabbage | Transplant outdoors (fall) | Jul 13 – Aug 13 |
| Leaf lettuce | Sow outdoors (spring) | Apr 6 – Jun 22 |
| Leaf lettuce | Sow outdoors (fall) | Jul 13 – Aug 29 |
| Spinach | Sow outdoors (spring) | Mar 30 – May 13 |
| Spinach | Sow outdoors (fall) | Jul 30 – Sep 3 |
| Radishes | Sow outdoors (spring) | Apr 6 – May 27 |
| Radishes | Sow outdoors (fall) | Jul 13 – Sep 13 |
| Kale | Sow outdoors (spring) | Apr 23 – May 13 |
| Kale | Sow outdoors (fall) | Jul 6 – Aug 13 |
| Carrots | Sow outdoors (spring) | May 7 – Jun 22 |
| Carrots | Sow outdoors (fall) | Jun 13 – Jul 29 |
| Garlic | Plant outdoors (fall) | Oct 13 – Nov 13 |
Where these dates come from
ZIP code 49701 is matched to the NOAA station St Ignace Mackinac Br, MI, 7.9 km away, at 595 ft elevation (1 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| St Ignace Mackinac Br, MI (used) | 595 ft | May 7 | Oct 23 |
| St Ignace, MI | 661 ft | May 16 | Oct 13 |
| Pellston Ap #2, MI | 712 ft | May 21 | Sep 27 |
| Pellston Rgnl Ap, MI | 705 ft | May 31 | Sep 18 |
Frost dates near Mackinaw City
- Carp Lake, MI 49718 · last May 7, first Oct 23
- Mackinac Island, MI 49757 · last May 7, first Oct 23
- Levering, MI 49755 · last May 31, first Sep 18
- Pointe Aux Pins, MI 49775 · last May 11, first Oct 11
- Pellston, MI 49769 · last May 31, first Sep 18
- Saint Ignace, MI 49781 · last May 23, first Sep 30
- Cheboygan, MI 49721 · last May 11, first Oct 11
- Mullett Lake, MI 49761 · last May 11, first Oct 11
Frequently asked questions
- When is the last frost in Mackinaw City, MI?
- For ZIP code 49701, the average last spring frost (32°F) is May 7, based on NOAA 1991-2020 climate normals for the St Ignace Mackinac Br, MI weather station. There is a 1-in-10 chance of a frost after May 22.
- When is the first frost in Mackinaw City, MI?
- The average first fall frost (32°F) is October 23. There is a 1-in-10 chance of frost by October 6, so tender plants are at risk from that point on.
- How long is the growing season in 49701?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 167 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.