Wyoming, Michigan: planting zone & frost dates
Wyoming is in USDA plant hardiness zone 6a, where the average coldest winter night reaches -10 to -5°F (-23.3 to -20.6°C). The typical last spring frost is around May 4 and the first fall frost around Oct 13.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | May 15 | Oct 4 |
| Typical planning date (30% risk) | May 4 | Oct 13 |
| Median (50%) | Apr 29 | Oct 20 |
How to read this: after the spring "10% risk" date, a 32°F frost happens in only about 1 year in 10. In fall, the "10% risk" date is the early end — a frost before it happens about 1 year in 10.
Frost data comes from NOAA station GRAND RAPIDS, MI (USW00094860), 8.2 mi (13.2 km) from the city center and 115 ft higher than the city center (+35 m). Record used for the 1991–2020 normals: 29 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Wyoming
All 4 ZIP codes covering Wyoming are in zone 6a.
Vegetable planting calendar for Wyoming
Dates are counted from the 30%-risk frost dates above (last frost May 4, first frost Oct 13). Shift a week later in cold spots or low-lying ground.
| Crop | Start indoors | Transplant / plant out | Direct sow | Fall crop sow/plant |
|---|---|---|---|---|
| Tomato | Mar 9 – Mar 23 | May 11 – May 25 | — | — |
| Pepper | Feb 23 – Mar 9 | May 18 – Jun 1 | — | — |
| Lettuce | Mar 23 – Apr 6 | Apr 20 – May 11 | Apr 6 – May 18 | Aug 4 – Sep 1 |
| Green Beans | — | — | May 11 – Jun 15 | Jul 21 – Aug 4 |
| Sweet Corn | — | — | May 11 – Jun 8 | — |
| Zucchini & Summer Squash | Apr 6 – Apr 13 | May 11 – May 25 | May 11 – Jun 1 | Jul 21 – Aug 4 |
| Cucumber | Apr 6 – Apr 13 | May 18 – May 25 | May 11 – Jun 1 | Jul 21 – Aug 4 |
| Carrot | — | — | Apr 13 – May 18 | Jul 21 – Aug 4 |
| Onion | Feb 9 – Feb 23 | Apr 6 – Apr 20 | — | — |
| Potato | — | Apr 6 – Apr 27 | — | — |
| Basil | Mar 23 – Apr 6 | May 18 – Jun 1 | May 18 – Jun 8 | — |
| Spinach | — | — | Mar 23 – Apr 20 | Aug 18 – Sep 15 |
| Kale | Mar 9 – Mar 23 | Apr 6 – Apr 27 | Apr 6 – Apr 27 | Aug 4 – Sep 1 |
| Broccoli | Mar 9 – Mar 23 | Apr 20 – May 11 | — | Jul 21 – Aug 4 |
| Peas | — | — | Mar 23 – Apr 13 | Aug 4 – Aug 18 |
| Eggplant | Feb 23 – Mar 9 | May 18 – Jun 1 | — | — |
| Cabbage | Mar 9 – Mar 23 | Apr 6 – Apr 20 | — | Jul 21 – Aug 4 |
| Radish | — | — | Mar 30 – May 18 | Sep 1 – Sep 29 |
| Strawberry | — | Apr 6 – Apr 27 | — | — |
| Beets | — | — | Apr 13 – May 25 | Aug 4 – Aug 18 |
Nearby cities in Michigan
- Grand Rapids — zone 6a, last frost May 4, first frost Oct 13
- Lansing — zone 6a, last frost May 7, first frost Oct 6
- Flint — zone 6a, last frost May 10, first frost Oct 7
- Ann Arbor — zone 6a, last frost May 11, first frost Oct 4
- Farmington Hills — zone 6a, last frost May 8, first frost Oct 10
- Livonia — zone 6b, last frost May 8, first frost Oct 10
More: all Michigan cities · other zone 6a cities: Chicago, IL, Denver, CO, Milwaukee, WI, Colorado Springs, CO, Omaha, NE, Aurora, CO, Lincoln, NE, Fort Wayne, IN
Wyoming gardening questions
When is the last frost in Wyoming, MI?
Plan around May 4. At NOAA's Grand Rapids, MI station, 8.2 mi from the city center, there is a 30% chance of a 32°F frost after that date. Half of springs have their last frost by Apr 29, and after May 15 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Apr 16. The 90% and 10% dates are 31 days apart, close to the 36-day median for cities on this site.
When should I plant tomatoes in Wyoming, MI?
Start seeds indoors Mar 9 – Mar 23 and set transplants outside May 11 – May 25, once nights stay above 50°F and the soil is near 60°F. That leaves 162 days between the 30% frost dates, enough for most varieties including 80–85-day slicers. More: tomato planting dates by zone.
How long is the growing season in Wyoming?
About 174 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 151 days, and in 1 year in 10 it runs 195 days or more. In fall there is a 10% chance of frost by Oct 4 and a 30% chance by Oct 13. That ranks 8th longest of 15 Michigan cities on this site.
When should I plant a fall garden in Wyoming?
Count back from the first fall frost (Oct 13): transplant broccoli Jul 21 – Aug 4; sow kale Aug 4 – Sep 1; sow lettuce Aug 4 – Sep 1; sow radishes Sep 1 – Sep 29. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Nov 2. How the math works: succession and fall planting.
Did Wyoming's hardiness zone change on the 2023 map?
Yes. Most of Wyoming was zone 5b on the 2012 map and is zone 6a on the 2023 map — half a zone warmer, like about 56% of U.S. ZIP codes. The shift comes from a newer 1991–2020 averaging period plus more weather stations and better mapping; it does not mean last frost comes earlier. Why the 2023 map is warmer.
How does Wyoming compare with Lansing, MI?
Both are in zone 6a. The typical last spring frost in Wyoming (May 4) comes about the same time as in Lansing, MI (May 7), 59 miles away, and the first fall frost is Oct 13 versus Oct 6. Wyoming sits about 191 ft lower, which explains part of the gap. The two cities use different NOAA stations.