Harrison, MI frost dates
Last spring frostMay 9median date
First fall frostOct 4median date
Growing season148 daysfrost-free
Hardiness zone5aZone 5a
How Harrison compares
- In 8 years out of 10, the last spring frost in Harrison falls between April 26 and May 23, a 27-day window. The first fall frost falls between September 22 and October 19.
- The median last frost is 4 days later than the Michigan median of May 5.
- Its 148-day growing season is longer than 31% of the 878 Michigan places with a regular frost season (state median 162 days).
- The last frost is 6 days later than the zone 5a median of May 3. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 5a chart.
- The weather station records an average of 165 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 26 |
| 50% (median) | May 9 |
| 10% (safe for tender plants) | May 23 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 22 |
| 50% (median) | October 4 |
| 90% (late) | October 19 |
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 Harrison, MI
Harrison, MI frost dates — last frost May 9, first frost Oct 4, zone 5a. whenisthelastfrost.com
Crop
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Start indoors: Feb 14 to Feb 28Transplant outside: Apr 11 to Apr 25
Start indoors: Feb 28 to Mar 14Transplant outside: May 23 to Jun 6
Start indoors: Feb 28 to Mar 14Transplant outside: May 23 to Jun 6
Start indoors: Mar 14 to Mar 28Transplant outside: May 16 to May 30
Start indoors: Mar 14 to Mar 28Transplant outside: Apr 18 to May 2Sow outdoors: Apr 11 to May 16Plant for fall: Aug 9 to Sep 6
Start indoors: Mar 14 to Mar 28Transplant outside: Apr 11 to Apr 25Sow outdoors: Apr 11 to Apr 25Plant for fall: Jul 26 to Aug 16
Start indoors: Mar 14 to Mar 28Transplant outside: Apr 25 to May 9Plant for fall: Jun 28 to Jul 19
Start indoors: Mar 14 to Mar 28Transplant outside: Apr 18 to May 2Plant for fall: Jun 28 to Jul 19
Start indoors: Mar 14 to Mar 28Transplant outside: Apr 25 to May 9Plant for fall: Jun 28 to Jul 19
Start indoors: Mar 28 to Apr 11Transplant outside: May 30 to Jun 13Sow outdoors: May 30 to Jun 13
Start indoors: Mar 28 to Apr 11Transplant outside: May 16 to May 30
Sow outdoors: Mar 28 to Apr 18Plant for fall: Jul 12 to Aug 2
Sow outdoors: Mar 28 to Apr 18Plant for fall: Aug 9 to Aug 30
Sow outdoors: Apr 4 to May 16Plant for fall: Aug 23 to Sep 13
Start indoors: Apr 11 to Apr 18Transplant outside: May 23 to May 30Sow outdoors: May 16 to May 30Plant for fall: Jul 19 to Aug 2
Start indoors: Apr 11 to Apr 18Sow outdoors: May 16 to May 30Plant for fall: Jul 26 to Aug 9
Start indoors: Apr 11 to Apr 18Sow outdoors: May 16 to May 30
Start indoors: Apr 11 to Apr 18Transplant outside: May 23 to Jun 6
Sow outdoors: Apr 18 to May 16Plant for fall: Jul 12 to Jul 26
Sow outdoors: Apr 18 to May 16Plant for fall: Jul 26 to Aug 9
Sow outdoors: Apr 18 to May 9
Sow outdoors: Apr 25 to May 23Plant for fall: Jul 26 to Aug 9
Sow outdoors: Apr 25 to May 16Plant for fall: Aug 9 to Aug 30
Sow outdoors: May 16 to Jun 6Plant for fall: Jul 19 to Aug 2
Sow outdoors: May 16 to May 30
Transplant outside: May 23 to Jun 13
Plant for fall: Sep 20 to Oct 25
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Harrison, MI
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 14 – Feb 28 | Apr 11 – Apr 25 | — | — |
| Peppers | Feb 28 – Mar 14 | May 23 – Jun 6 | — | — |
| Eggplant | Feb 28 – Mar 14 | May 23 – Jun 6 | — | — |
| Tomatoes | Mar 14 – Mar 28 | May 16 – May 30 | — | — |
| Lettuce | Mar 14 – Mar 28 | Apr 18 – May 2 | Apr 11 – May 16 | Aug 9 – Sep 6 |
| Kale | Mar 14 – Mar 28 | Apr 11 – Apr 25 | Apr 11 – Apr 25 | Jul 26 – Aug 16 |
| Broccoli | Mar 14 – Mar 28 | Apr 25 – May 9 | — | Jun 28 – Jul 19 |
| Cabbage | Mar 14 – Mar 28 | Apr 18 – May 2 | — | Jun 28 – Jul 19 |
| Cauliflower | Mar 14 – Mar 28 | Apr 25 – May 9 | — | Jun 28 – Jul 19 |
| Okra | Mar 28 – Apr 11 | May 30 – Jun 13 | May 30 – Jun 13 | — |
| Basil | Mar 28 – Apr 11 | May 16 – May 30 | — | — |
| Peas | — | — | Mar 28 – Apr 18 | Jul 12 – Aug 2 |
| Spinach | — | — | Mar 28 – Apr 18 | Aug 9 – Aug 30 |
| Radishes | — | — | Apr 4 – May 16 | Aug 23 – Sep 13 |
| Cucumbers | Apr 11 – Apr 18 | May 23 – May 30 | May 16 – May 30 | Jul 19 – Aug 2 |
| Zucchini & Summer Squash | Apr 11 – Apr 18 | — | May 16 – May 30 | Jul 26 – Aug 9 |
| Winter Squash & Pumpkins | Apr 11 – Apr 18 | — | May 16 – May 30 | — |
| Melons & Watermelon | Apr 11 – Apr 18 | May 23 – Jun 6 | — | — |
| Carrots | — | — | Apr 18 – May 16 | Jul 12 – Jul 26 |
| Beets | — | — | Apr 18 – May 16 | Jul 26 – Aug 9 |
| Potatoes | — | — | Apr 18 – May 9 | — |
| Swiss Chard | — | — | Apr 25 – May 23 | Jul 26 – Aug 9 |
| Cilantro | — | — | Apr 25 – May 16 | Aug 9 – Aug 30 |
| Green Beans | — | — | May 16 – Jun 6 | Jul 19 – Aug 2 |
| Sweet Corn | — | — | May 16 – May 30 | — |
| Sweet Potatoes | — | May 23 – Jun 13 | — | — |
| Garlic | — | — | — | Sep 20 – Oct 25 |
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 Gladwin, MI weather station, 23 km away (elevation 774 ft (236 m)).
Frost dates near Harrison
- Lake George May 9 · Oct 4
- Gladwin May 9 · Oct 4
- Clare Apr 30 · Oct 20
- Farwell Apr 30 · Oct 20
- Lake Apr 30 · Oct 20
- Marion May 15 · Oct 1
- Prudenville May 19 · Sep 23
- Falmouth May 30 · Sep 15
- Houghton Lake May 20 · Oct 1
- Beaverton May 9 · Oct 4
Frequently asked questions
When is the last frost in Harrison, MI?
The median last spring frost in Harrison, MI is May 9. There is still about a 10% chance of frost after May 23, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Harrison, MI?
The median first fall frost is October 4, with about a 10% chance of frost before September 22.
How long is the growing season in Harrison, MI?
About 148 days between the median last spring frost and first fall frost.
What planting zone is Harrison, MI?
Harrison, MI is in USDA hardiness zone 5a.