Frost dates for 49420Hart, MI
The average last spring frost in Hart is May 12 and the average first fall frost is October 10, giving a typical growing season of about 151 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 12
- Average first fall frost
- Oct 10
- Growing season
- 151 days
Safer after May 28 (1-in-10 risk)
Possible by Sep 25 (1-in-10 risk)
Last frost typically in 191 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 7 · May 24 · Jun 6 | Sep 14 · Sep 29 · Oct 13 | 128 days | 100% |
| Frost / freeze (32°F) | Apr 25 · May 12 · May 28 | Sep 25 · Oct 10 · Oct 26 | 151 days | 100% |
| Hard freeze (28°F) | Apr 14 · Apr 30 · May 20 | Oct 8 · Oct 25 · Nov 7 | 174 days | 100% |
Planting calendar for Hart
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 11 – Jun 17 |
| Tomatoes | Transplant outdoors | May 28 – Jun 20 |
| Peppers | Start seeds indoors | Apr 11 – May 12 |
| Peppers | Transplant outdoors | Jun 11 – Jul 12 |
| Eggplant | Start seeds indoors | Apr 28 – May 27 |
| Eggplant | Transplant outdoors | Jun 11 – Jul 12 |
| Cucumbers | Sow outdoors | Jun 11 – Jun 30 |
| Summer squash | Sow outdoors | May 28 – Jul 12 |
| Winter squash & pumpkins | Sow outdoors | Jun 11 – Jul 12 |
| Snap beans | Sow outdoors | May 28 – Jul 23 |
| Sweet corn | Sow outdoors | May 28 – Jun 20 |
| Watermelon & cantaloupe | Sow outdoors | Jun 11 – Jul 12 |
| Okra | Sow outdoors | Jun 4 – Jun 27 |
| Peas | Sow outdoors (spring) | Apr 11 – May 27 |
| Potatoes | Plant outdoors (spring) | Apr 11 – Jun 11 |
| Onions | Start seeds indoors (spring) | Feb 28 – Mar 27 |
| Onions | Transplant outdoors (spring) | Apr 28 – May 27 |
| Broccoli | Start seeds indoors (spring) | Mar 24 – Apr 27 |
| Broccoli | Transplant outdoors (spring) | Apr 28 – May 27 |
| Broccoli | Start seeds indoors (fall) | Jun 10 – Jun 20 |
| Broccoli | Transplant outdoors (fall) | Jul 10 – Jul 21 |
| Cabbage | Start seeds indoors (spring) | Mar 14 – Apr 11 |
| Cabbage | Transplant outdoors (spring) | Apr 11 – May 12 |
| Cabbage | Start seeds indoors (fall) | May 31 – Jun 30 |
| Cabbage | Transplant outdoors (fall) | Jun 30 – Jul 31 |
| Leaf lettuce | Sow outdoors (spring) | Apr 11 – Jun 27 |
| Leaf lettuce | Sow outdoors (fall) | Jun 30 – Aug 16 |
| Spinach | Sow outdoors (spring) | Apr 4 – May 18 |
| Spinach | Sow outdoors (fall) | Jul 17 – Aug 21 |
| Radishes | Sow outdoors (spring) | Apr 11 – Jun 1 |
| Radishes | Sow outdoors (fall) | Jun 30 – Aug 31 |
| Kale | Sow outdoors (spring) | Apr 28 – May 18 |
| Kale | Sow outdoors (fall) | Jun 23 – Jul 31 |
| Carrots | Sow outdoors (spring) | May 12 – Jun 27 |
| Carrots | Sow outdoors (fall) | May 31 – Jul 16 |
| Garlic | Plant outdoors (fall) | Sep 30 – Oct 31 |
Where these dates come from
ZIP code 49420 is matched to the NOAA station Hart 3 Wsw, MI, 9.5 km away, at 770 ft elevation (94 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Hart 3 Wsw, MI (used) | 770 ft | May 12 | Oct 10 |
| Hesperia 4 Wnw, MI | 780 ft | May 17 | Oct 1 |
| Ludington 4 Se, MI | 690 ft | May 17 | Oct 7 |
| Montague 4 Nw, MI | 650 ft | May 19 | Oct 4 |
Frost dates near Hart
- Mears, MI 49436 · last May 12, first Oct 10
- Shelby, MI 49455 · last May 12, first Oct 10
- Pentwater, MI 49449 · last May 12, first Oct 10
- New Era, MI 49446 · last May 12, first Oct 10
- Walkerville, MI 49459 · last May 17, first Oct 1
- Rothbury, MI 49452 · last May 19, first Oct 4
- Hesperia, MI 49421 · last May 17, first Oct 1
- Custer, MI 49405 · last May 14, first Oct 12
Frequently asked questions
- When is the last frost in Hart, MI?
- For ZIP code 49420, the average last spring frost (32°F) is May 12, based on NOAA 1991-2020 climate normals for the Hart 3 Wsw, MI weather station. There is a 1-in-10 chance of a frost after May 28.
- When is the first frost in Hart, MI?
- The average first fall frost (32°F) is October 10. There is a 1-in-10 chance of frost by September 25, so tender plants are at risk from that point on.
- How long is the growing season in 49420?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 151 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.