Decatur, MI frost dates
Last spring frostMay 4median date
First fall frostOct 11median date
Growing season160 daysfrost-free
Hardiness zone6aZone 6a
How Decatur compares
- In 8 years out of 10, the last spring frost in Decatur falls between April 21 and May 22, a 31-day window. The first fall frost falls between September 27 and October 27.
- The median last frost is 1 day earlier than the Michigan median of May 5.
- Its 160-day growing season is longer than 46% of the 878 Michigan places with a regular frost season (state median 162 days).
- The last frost is 5 days later than the zone 6a median of Apr 29. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 6a chart.
- The weather station records an average of 145 nights a year at or below 32°F.
- Compared with Kalamazoo, MI, 43 km away, the last frost here is 6 days later than there and the growing season is 13 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 21 |
| 50% (median) | May 4 |
| 10% (safe for tender plants) | May 22 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 27 |
| 50% (median) | October 11 |
| 90% (late) | October 27 |
Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.
Planting calendar for Decatur, MI
Decatur, MI frost dates — last frost May 4, first frost Oct 11, zone 6a. whenisthelastfrost.com
Crop
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Start indoors: Feb 9 to Feb 23Transplant outside: Apr 6 to Apr 20
Start indoors: Feb 23 to Mar 9Transplant outside: May 18 to Jun 1
Start indoors: Feb 23 to Mar 9Transplant outside: May 18 to Jun 1
Start indoors: Mar 9 to Mar 23Transplant outside: May 11 to May 25
Start indoors: Mar 9 to Mar 23Transplant outside: Apr 13 to Apr 27Sow outdoors: Apr 6 to May 11Plant for fall: Aug 16 to Sep 13
Start indoors: Mar 9 to Mar 23Transplant outside: Apr 6 to Apr 20Sow outdoors: Apr 6 to Apr 20Plant for fall: Aug 2 to Aug 23
Start indoors: Mar 9 to Mar 23Transplant outside: Apr 20 to May 4Plant for fall: Jul 5 to Jul 26
Start indoors: Mar 9 to Mar 23Transplant outside: Apr 13 to Apr 27Plant for fall: Jul 5 to Jul 26
Start indoors: Mar 9 to Mar 23Transplant outside: Apr 20 to May 4Plant for fall: Jul 5 to Jul 26
Start indoors: Mar 23 to Apr 6Transplant outside: May 25 to Jun 8Sow outdoors: May 25 to Jun 8
Start indoors: Mar 23 to Apr 6Transplant outside: May 11 to May 25
Sow outdoors: Mar 23 to Apr 13Plant for fall: Jul 19 to Aug 9
Sow outdoors: Mar 23 to Apr 13Plant for fall: Aug 16 to Sep 6
Sow outdoors: Mar 30 to May 11Plant for fall: Aug 30 to Sep 20
Start indoors: Apr 6 to Apr 13Transplant outside: May 18 to May 25Sow outdoors: May 11 to May 25Plant for fall: Jul 26 to Aug 9
Start indoors: Apr 6 to Apr 13Sow outdoors: May 11 to May 25Plant for fall: Aug 2 to Aug 16
Start indoors: Apr 6 to Apr 13Sow outdoors: May 11 to May 25
Start indoors: Apr 6 to Apr 13Transplant outside: May 18 to Jun 1
Sow outdoors: Apr 13 to May 11Plant for fall: Jul 19 to Aug 2
Sow outdoors: Apr 13 to May 11Plant for fall: Aug 2 to Aug 16
Sow outdoors: Apr 13 to May 4
Sow outdoors: Apr 20 to May 18Plant for fall: Aug 2 to Aug 16
Sow outdoors: Apr 20 to May 11Plant for fall: Aug 16 to Sep 6
Sow outdoors: May 11 to Jun 1Plant for fall: Jul 26 to Aug 9
Sow outdoors: May 11 to May 25
Transplant outside: May 18 to Jun 8
Plant for fall: Sep 27 to Nov 1
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Decatur, MI
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 9 – Feb 23 | Apr 6 – Apr 20 | — | — |
| Peppers | Feb 23 – Mar 9 | May 18 – Jun 1 | — | — |
| Eggplant | Feb 23 – Mar 9 | May 18 – Jun 1 | — | — |
| Tomatoes | Mar 9 – Mar 23 | May 11 – May 25 | — | — |
| Lettuce | Mar 9 – Mar 23 | Apr 13 – Apr 27 | Apr 6 – May 11 | Aug 16 – Sep 13 |
| Kale | Mar 9 – Mar 23 | Apr 6 – Apr 20 | Apr 6 – Apr 20 | Aug 2 – Aug 23 |
| Broccoli | Mar 9 – Mar 23 | Apr 20 – May 4 | — | Jul 5 – Jul 26 |
| Cabbage | Mar 9 – Mar 23 | Apr 13 – Apr 27 | — | Jul 5 – Jul 26 |
| Cauliflower | Mar 9 – Mar 23 | Apr 20 – May 4 | — | Jul 5 – Jul 26 |
| Okra | Mar 23 – Apr 6 | May 25 – Jun 8 | May 25 – Jun 8 | — |
| Basil | Mar 23 – Apr 6 | May 11 – May 25 | — | — |
| Peas | — | — | Mar 23 – Apr 13 | Jul 19 – Aug 9 |
| Spinach | — | — | Mar 23 – Apr 13 | Aug 16 – Sep 6 |
| Radishes | — | — | Mar 30 – May 11 | Aug 30 – Sep 20 |
| Cucumbers | Apr 6 – Apr 13 | May 18 – May 25 | May 11 – May 25 | Jul 26 – Aug 9 |
| Zucchini & Summer Squash | Apr 6 – Apr 13 | — | May 11 – May 25 | Aug 2 – Aug 16 |
| Winter Squash & Pumpkins | Apr 6 – Apr 13 | — | May 11 – May 25 | — |
| Melons & Watermelon | Apr 6 – Apr 13 | May 18 – Jun 1 | — | — |
| Carrots | — | — | Apr 13 – May 11 | Jul 19 – Aug 2 |
| Beets | — | — | Apr 13 – May 11 | Aug 2 – Aug 16 |
| Potatoes | — | — | Apr 13 – May 4 | — |
| Swiss Chard | — | — | Apr 20 – May 18 | Aug 2 – Aug 16 |
| Cilantro | — | — | Apr 20 – May 11 | Aug 16 – Sep 6 |
| Green Beans | — | — | May 11 – Jun 1 | Jul 26 – Aug 9 |
| Sweet Corn | — | — | May 11 – May 25 | — |
| Sweet Potatoes | — | May 18 – Jun 8 | — | — |
| Garlic | — | — | — | Sep 27 – Nov 1 |
Dates come from the median frost dates and common extension-service timing. Adjust for your soil temperature, microclimate and the varieties you grow.
About these dates
Based on 1991–2020 NOAA climate normals for the Dowagiac 1 W, MI weather station, 15 km away (elevation 741 ft (226 m)).
Frost dates near Decatur
- Lawrence May 7 · Oct 11
- Dowagiac May 4 · Oct 11
- Hartford Apr 22 · Oct 30
- Lawton Apr 28 · Oct 18
- Paw Paw May 7 · Oct 11
- Marcellus Apr 30 · Oct 17
- Watervliet May 5 · Oct 15
- Cassopolis May 4 · Oct 11
- Eau Claire Apr 22 · Oct 30
- Mattawan Apr 28 · Oct 18
Frequently asked questions
When is the last frost in Decatur, MI?
The median last spring frost in Decatur, MI is May 4. There is still about a 10% chance of frost after May 22, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Decatur, MI?
The median first fall frost is October 11, with about a 10% chance of frost before September 27.
How long is the growing season in Decatur, MI?
About 160 days between the median last spring frost and first fall frost.
What planting zone is Decatur, MI?
Decatur, MI is in USDA hardiness zone 6a.