Frost dates for 49261Napoleon, MI
The average last spring frost in Napoleon is April 30 and the average first fall frost is October 14, giving a typical growing season of about 165 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 30
- Average first fall frost
- Oct 14
- Growing season
- 165 days
Safer after May 16 (1-in-10 risk)
Possible by Oct 1 (1-in-10 risk)
Last frost typically in 180 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 26 · May 10 · May 26 | Sep 19 · Oct 3 · Oct 16 | 144 days | 100% |
| Frost / freeze (32°F) | Apr 16 · Apr 30 · May 16 | Oct 1 · Oct 14 · Oct 29 | 165 days | 100% |
| Hard freeze (28°F) | Apr 6 · Apr 19 · May 5 | Oct 11 · Oct 27 · Nov 10 | 188 days | 100% |
Planting calendar for Napoleon
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 | Mar 30 – Jun 5 |
| Tomatoes | Transplant outdoors | May 16 – Jun 24 |
| Peppers | Start seeds indoors | Mar 30 – Apr 30 |
| Peppers | Transplant outdoors | May 30 – Jun 30 |
| Eggplant | Start seeds indoors | Apr 16 – May 15 |
| Eggplant | Transplant outdoors | May 30 – Jun 30 |
| Cucumbers | Sow outdoors | May 30 – Jul 4 |
| Summer squash | Sow outdoors | May 16 – Jun 30 |
| Winter squash & pumpkins | Sow outdoors | May 30 – Jun 30 |
| Snap beans | Sow outdoors | May 16 – Jul 27 |
| Sweet corn | Sow outdoors | May 16 – Jun 24 |
| Watermelon & cantaloupe | Sow outdoors | May 30 – Jun 30 |
| Okra | Sow outdoors | May 23 – Jun 15 |
| Peas | Sow outdoors (spring) | Mar 30 – May 15 |
| Potatoes | Plant outdoors (spring) | Mar 30 – May 30 |
| Onions | Start seeds indoors (spring) | Feb 16 – Mar 15 |
| Onions | Transplant outdoors (spring) | Apr 16 – May 15 |
| Broccoli | Start seeds indoors (spring) | Mar 12 – Apr 15 |
| Broccoli | Transplant outdoors (spring) | Apr 16 – May 15 |
| Broccoli | Start seeds indoors (fall) | Jun 14 – Jun 24 |
| Broccoli | Transplant outdoors (fall) | Jul 14 – Jul 25 |
| Cabbage | Start seeds indoors (spring) | Mar 2 – Mar 30 |
| Cabbage | Transplant outdoors (spring) | Mar 30 – Apr 30 |
| Cabbage | Start seeds indoors (fall) | Jun 4 – Jul 4 |
| Cabbage | Transplant outdoors (fall) | Jul 4 – Aug 4 |
| Leaf lettuce | Sow outdoors (spring) | Mar 30 – Jun 15 |
| Leaf lettuce | Sow outdoors (fall) | Jul 4 – Aug 20 |
| Spinach | Sow outdoors (spring) | Mar 23 – May 6 |
| Spinach | Sow outdoors (fall) | Jul 21 – Aug 25 |
| Radishes | Sow outdoors (spring) | Mar 30 – May 20 |
| Radishes | Sow outdoors (fall) | Jul 4 – Sep 4 |
| Kale | Sow outdoors (spring) | Apr 16 – May 6 |
| Kale | Sow outdoors (fall) | Jun 27 – Aug 4 |
| Carrots | Sow outdoors (spring) | Apr 30 – Jun 15 |
| Carrots | Sow outdoors (fall) | Jun 4 – Jul 20 |
| Garlic | Plant outdoors (fall) | Oct 4 – Nov 4 |
Where these dates come from
ZIP code 49261 is matched to the NOAA station Manchester, MI, 18.4 km away, at 965 ft elevation (0 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Manchester, MI (used) | 965 ft | Apr 30 | Oct 14 |
| Tipton 2Wnw, MI | 970 ft | May 5 | Oct 10 |
| Jackson Reynolds Fld, MI | 998 ft | May 1 | Oct 14 |
| Chelsea, MI | 900 ft | Apr 30 | Oct 12 |
Frost dates near Napoleon
- Norvell, MI 49263 · last Apr 30, first Oct 14
- Brooklyn, MI 49230 · last Apr 30, first Oct 14
- Michigan Center, MI 49254 · last May 1, first Oct 14
- Clarklake, MI 49234 · last May 1, first Oct 14
- Grass Lake, MI 49240 · last Apr 30, first Oct 12
- Cement City, MI 49233 · last May 1, first Oct 14
- Jackson, MI 49201 · last May 1, first Oct 14
- Onsted, MI 49265 · last Apr 30, first Oct 14
Frequently asked questions
- When is the last frost in Napoleon, MI?
- For ZIP code 49261, the average last spring frost (32°F) is April 30, based on NOAA 1991-2020 climate normals for the Manchester, MI weather station. There is a 1-in-10 chance of a frost after May 16.
- When is the first frost in Napoleon, MI?
- The average first fall frost (32°F) is October 14. There is a 1-in-10 chance of frost by October 1, so tender plants are at risk from that point on.
- How long is the growing season in 49261?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 165 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.