Frost dates for 49081Portage, MI
The average last spring frost in Portage is April 28 and the average first fall frost is October 18, giving a typical growing season of about 172 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 28
- Average first fall frost
- Oct 18
- Growing season
- 172 days
Safer after May 13 (1-in-10 risk)
Possible by Oct 2 (1-in-10 risk)
Last frost typically in 177 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 24 · May 8 · May 24 | Sep 22 · Oct 6 · Oct 19 | 149 days | 100% |
| Frost / freeze (32°F) | Apr 13 · Apr 28 · May 13 | Oct 2 · Oct 18 · Nov 1 | 172 days | 100% |
| Hard freeze (28°F) | Apr 3 · Apr 17 · May 3 | Oct 16 · Nov 1 · Nov 14 | 196 days | 100% |
Planting calendar for Portage
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 28 – Jun 3 |
| Tomatoes | Transplant outdoors | May 14 – Jun 28 |
| Peppers | Start seeds indoors | Mar 28 – Apr 28 |
| Peppers | Transplant outdoors | May 28 – Jun 28 |
| Eggplant | Start seeds indoors | Apr 14 – May 13 |
| Eggplant | Transplant outdoors | May 28 – Jun 28 |
| Cucumbers | Sow outdoors | May 28 – Jul 8 |
| Summer squash | Sow outdoors | May 14 – Jun 28 |
| Winter squash & pumpkins | Sow outdoors | May 28 – Jun 28 |
| Snap beans | Sow outdoors | May 14 – Jul 31 |
| Sweet corn | Sow outdoors | May 14 – Jun 28 |
| Watermelon & cantaloupe | Sow outdoors | May 28 – Jun 28 |
| Okra | Sow outdoors | May 21 – Jun 13 |
| Peas | Sow outdoors (spring) | Mar 28 – May 13 |
| Potatoes | Plant outdoors (spring) | Mar 28 – May 28 |
| Onions | Start seeds indoors (spring) | Feb 14 – Mar 13 |
| Onions | Transplant outdoors (spring) | Apr 14 – May 13 |
| Broccoli | Start seeds indoors (spring) | Mar 10 – Apr 13 |
| Broccoli | Transplant outdoors (spring) | Apr 14 – May 13 |
| Broccoli | Start seeds indoors (fall) | Jun 18 – Jun 28 |
| Broccoli | Transplant outdoors (fall) | Jul 18 – Jul 29 |
| Cabbage | Start seeds indoors (spring) | Feb 28 – Mar 28 |
| Cabbage | Transplant outdoors (spring) | Mar 28 – Apr 28 |
| Cabbage | Start seeds indoors (fall) | Jun 8 – Jul 8 |
| Cabbage | Transplant outdoors (fall) | Jul 8 – Aug 8 |
| Leaf lettuce | Sow outdoors (spring) | Mar 28 – Jun 13 |
| Leaf lettuce | Sow outdoors (fall) | Jul 8 – Aug 24 |
| Spinach | Sow outdoors (spring) | Mar 21 – May 4 |
| Spinach | Sow outdoors (fall) | Jul 25 – Aug 29 |
| Radishes | Sow outdoors (spring) | Mar 28 – May 18 |
| Radishes | Sow outdoors (fall) | Jul 8 – Sep 8 |
| Kale | Sow outdoors (spring) | Apr 14 – May 4 |
| Kale | Sow outdoors (fall) | Jul 1 – Aug 8 |
| Carrots | Sow outdoors (spring) | Apr 28 – Jun 13 |
| Carrots | Sow outdoors (fall) | Jun 8 – Jul 24 |
| Garlic | Plant outdoors (fall) | Oct 8 – Nov 8 |
Where these dates come from
ZIP code 49081 is matched to the NOAA station Kalamazoo Battle Ck Intl Ap, MI, 8.9 km away, at 868 ft elevation (18 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Kalamazoo Battle Ck Intl Ap, MI (used) | 868 ft | Apr 28 | Oct 18 |
| Three Rivers, MI | 810 ft | Apr 30 | Oct 17 |
| Gull Lake Biological Stn, MI | 925 ft | Apr 29 | Oct 20 |
| Battle Creek Kellogg Ap, MI | 928 ft | Apr 30 | Oct 19 |
Frost dates near Portage
- Portage, MI 49024 · last Apr 28, first Oct 18
- Schoolcraft, MI 49087 · last Apr 28, first Oct 18
- Kalamazoo, MI 49008 · last Apr 28, first Oct 18
- Oshtemo, MI 49077 · last Apr 28, first Oct 18
- Nazareth, MI 49074 · last Apr 28, first Oct 18
- Vicksburg, MI 49097 · last Apr 28, first Oct 18
- Scotts, MI 49088 · last Apr 28, first Oct 18
- Comstock, MI 49041 · last Apr 28, first Oct 18
Frequently asked questions
- When is the last frost in Portage, MI?
- For ZIP code 49081, the average last spring frost (32°F) is April 28, based on NOAA 1991-2020 climate normals for the Kalamazoo Battle Ck Intl Ap, MI weather station. There is a 1-in-10 chance of a frost after May 13.
- When is the first frost in Portage, MI?
- The average first fall frost (32°F) is October 18. There is a 1-in-10 chance of frost by October 2, so tender plants are at risk from that point on.
- How long is the growing season in 49081?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 172 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.