Frost dates for 48843Howell, MI
The average last spring frost in Howell is May 4 and the average first fall frost is October 7, giving a typical growing season of about 156 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 4
- Average first fall frost
- Oct 7
- Growing season
- 156 days
Safer after May 21 (1-in-10 risk)
Possible by Sep 27 (1-in-10 risk)
Last frost typically in 183 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) | Apr 30 · May 16 · May 31 | Sep 17 · Sep 29 · Oct 10 | 136 days | 100% |
| Frost / freeze (32°F) | Apr 20 · May 4 · May 21 | Sep 27 · Oct 7 · Oct 21 | 156 days | 100% |
| Hard freeze (28°F) | Apr 11 · Apr 24 · May 11 | Oct 5 · Oct 20 · Nov 3 | 178 days | 100% |
Planting calendar for Howell
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 3 – Jun 9 |
| Tomatoes | Transplant outdoors | May 20 – Jun 17 |
| Peppers | Start seeds indoors | Apr 3 – May 4 |
| Peppers | Transplant outdoors | Jun 3 – Jul 4 |
| Eggplant | Start seeds indoors | Apr 20 – May 19 |
| Eggplant | Transplant outdoors | Jun 3 – Jul 4 |
| Cucumbers | Sow outdoors | Jun 3 – Jun 27 |
| Summer squash | Sow outdoors | May 20 – Jul 4 |
| Winter squash & pumpkins | Sow outdoors | Jun 3 – Jul 4 |
| Snap beans | Sow outdoors | May 20 – Jul 20 |
| Sweet corn | Sow outdoors | May 20 – Jun 17 |
| Watermelon & cantaloupe | Sow outdoors | Jun 3 – Jul 4 |
| Okra | Sow outdoors | May 27 – Jun 19 |
| Peas | Sow outdoors (spring) | Apr 3 – May 19 |
| Potatoes | Plant outdoors (spring) | Apr 3 – Jun 3 |
| Onions | Start seeds indoors (spring) | Feb 20 – Mar 19 |
| Onions | Transplant outdoors (spring) | Apr 20 – May 19 |
| Broccoli | Start seeds indoors (spring) | Mar 16 – Apr 19 |
| Broccoli | Transplant outdoors (spring) | Apr 20 – May 19 |
| Broccoli | Start seeds indoors (fall) | Jun 7 – Jun 17 |
| Broccoli | Transplant outdoors (fall) | Jul 7 – Jul 18 |
| Cabbage | Start seeds indoors (spring) | Mar 6 – Apr 3 |
| Cabbage | Transplant outdoors (spring) | Apr 3 – May 4 |
| Cabbage | Start seeds indoors (fall) | May 28 – Jun 27 |
| Cabbage | Transplant outdoors (fall) | Jun 27 – Jul 28 |
| Leaf lettuce | Sow outdoors (spring) | Apr 3 – Jun 19 |
| Leaf lettuce | Sow outdoors (fall) | Jun 27 – Aug 13 |
| Spinach | Sow outdoors (spring) | Mar 27 – May 10 |
| Spinach | Sow outdoors (fall) | Jul 14 – Aug 18 |
| Radishes | Sow outdoors (spring) | Apr 3 – May 24 |
| Radishes | Sow outdoors (fall) | Jun 27 – Aug 28 |
| Kale | Sow outdoors (spring) | Apr 20 – May 10 |
| Kale | Sow outdoors (fall) | Jun 20 – Jul 28 |
| Carrots | Sow outdoors (spring) | May 4 – Jun 19 |
| Carrots | Sow outdoors (fall) | May 28 – Jul 13 |
| Garlic | Plant outdoors (fall) | Sep 27 – Oct 28 |
Where these dates come from
ZIP code 48843 is matched to the NOAA station Howell Wwtp, MI, 2.5 km away, at 917 ft elevation (15 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Howell Wwtp, MI (used) | 917 ft | May 4 | Oct 7 |
| Milford Gm Proving Ground, MI | 970 ft | May 6 | Oct 12 |
| Hell, MI | 890 ft | Apr 30 | Oct 14 |
| Whitmore Lake 1Nw, MI | 906 ft | May 5 | Oct 13 |
Frost dates near Howell
- Howell, MI 48844 · last May 4, first Oct 7
- Fowlerville, MI 48836 · last May 3, first Oct 12
- Brighton, MI 48116 · last May 6, first Oct 12
- Cohoctah, MI 48816 · last May 3, first Oct 12
- Hartland, MI 48353 · last May 6, first Oct 12
- Pinckney, MI 48169 · last Apr 30, first Oct 12
- Gregory, MI 48137 · last Apr 30, first Oct 12
- Lakeland, MI 48143 · last May 5, first Oct 13
Frequently asked questions
- When is the last frost in Howell, MI?
- For ZIP code 48843, the average last spring frost (32°F) is May 4, based on NOAA 1991-2020 climate normals for the Howell Wwtp, MI weather station. There is a 1-in-10 chance of a frost after May 21.
- When is the first frost in Howell, MI?
- The average first fall frost (32°F) is October 7. There is a 1-in-10 chance of frost by September 27, so tender plants are at risk from that point on.
- How long is the growing season in 48843?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 156 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.