Frost dates for 49266Osseo, MI
The average last spring frost in Osseo is May 3 and the average first fall frost is October 12, giving a typical growing season of about 161 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 3
- Average first fall frost
- Oct 12
- Growing season
- 161 days
Safer after May 19 (1-in-10 risk)
Possible by Sep 29 (1-in-10 risk)
Last frost typically in 182 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 14 · May 30 | Sep 18 · Oct 1 · Oct 13 | 139 days | 100% |
| Frost / freeze (32°F) | Apr 20 · May 3 · May 19 | Sep 29 · Oct 12 · Oct 27 | 161 days | 100% |
| Hard freeze (28°F) | Apr 8 · Apr 23 · May 9 | Oct 10 · Oct 26 · Nov 8 | 184 days | 100% |
Planting calendar for Osseo
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 2 – Jun 8 |
| Tomatoes | Transplant outdoors | May 19 – Jun 22 |
| Peppers | Start seeds indoors | Apr 2 – May 3 |
| Peppers | Transplant outdoors | Jun 2 – Jul 3 |
| Eggplant | Start seeds indoors | Apr 19 – May 18 |
| Eggplant | Transplant outdoors | Jun 2 – Jul 3 |
| Cucumbers | Sow outdoors | Jun 2 – Jul 2 |
| Summer squash | Sow outdoors | May 19 – Jul 3 |
| Winter squash & pumpkins | Sow outdoors | Jun 2 – Jul 3 |
| Snap beans | Sow outdoors | May 19 – Jul 25 |
| Sweet corn | Sow outdoors | May 19 – Jun 22 |
| Watermelon & cantaloupe | Sow outdoors | Jun 2 – Jul 3 |
| Okra | Sow outdoors | May 26 – Jun 18 |
| Peas | Sow outdoors (spring) | Apr 2 – May 18 |
| Potatoes | Plant outdoors (spring) | Apr 2 – Jun 2 |
| Onions | Start seeds indoors (spring) | Feb 19 – Mar 18 |
| Onions | Transplant outdoors (spring) | Apr 19 – May 18 |
| Broccoli | Start seeds indoors (spring) | Mar 15 – Apr 18 |
| Broccoli | Transplant outdoors (spring) | Apr 19 – May 18 |
| Broccoli | Start seeds indoors (fall) | Jun 12 – Jun 22 |
| Broccoli | Transplant outdoors (fall) | Jul 12 – Jul 23 |
| Cabbage | Start seeds indoors (spring) | Mar 5 – Apr 2 |
| Cabbage | Transplant outdoors (spring) | Apr 2 – May 3 |
| Cabbage | Start seeds indoors (fall) | Jun 2 – Jul 2 |
| Cabbage | Transplant outdoors (fall) | Jul 2 – Aug 2 |
| Leaf lettuce | Sow outdoors (spring) | Apr 2 – Jun 18 |
| Leaf lettuce | Sow outdoors (fall) | Jul 2 – Aug 18 |
| Spinach | Sow outdoors (spring) | Mar 26 – May 9 |
| Spinach | Sow outdoors (fall) | Jul 19 – Aug 23 |
| Radishes | Sow outdoors (spring) | Apr 2 – May 23 |
| Radishes | Sow outdoors (fall) | Jul 2 – Sep 2 |
| Kale | Sow outdoors (spring) | Apr 19 – May 9 |
| Kale | Sow outdoors (fall) | Jun 25 – Aug 2 |
| Carrots | Sow outdoors (spring) | May 3 – Jun 18 |
| Carrots | Sow outdoors (fall) | Jun 2 – Jul 18 |
| Garlic | Plant outdoors (fall) | Oct 2 – Nov 2 |
Where these dates come from
ZIP code 49266 is matched to the NOAA station Hillsdale, MI, 11.4 km away, at 1,080 ft elevation (22 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Hillsdale, MI (used) | 1,080 ft | May 3 | Oct 12 |
| Montpelier, OH | 860 ft | Apr 28 | Oct 18 |
| Morenci, MI | 770 ft | May 4 | Oct 7 |
| Coldwater St School, MI | 984 ft | May 2 | Oct 13 |
Frost dates near Osseo
- Frontier, MI 49239 · last May 3, first Oct 12
- Hillsdale, MI 49242 · last May 3, first Oct 12
- Reading, MI 49274 · last May 3, first Oct 12
- Pittsford, MI 49271 · last May 3, first Oct 12
- Camden, MI 49232 · last Apr 28, first Oct 18
- North Adams, MI 49262 · last May 3, first Oct 12
- Jonesville, MI 49250 · last May 3, first Oct 12
- Waldron, MI 49288 · last Apr 28, first Oct 18
Frequently asked questions
- When is the last frost in Osseo, MI?
- For ZIP code 49266, the average last spring frost (32°F) is May 3, based on NOAA 1991-2020 climate normals for the Hillsdale, MI weather station. There is a 1-in-10 chance of a frost after May 19.
- When is the first frost in Osseo, MI?
- The average first fall frost (32°F) is October 12. There is a 1-in-10 chance of frost by September 29, so tender plants are at risk from that point on.
- How long is the growing season in 49266?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 161 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.