Grand Marais, MI frost dates
Last spring frostMay 27median date
First fall frostOct 10median date
Growing season136 daysfrost-free
Hardiness zone5bZone 5b
How Grand Marais compares
- In 8 years out of 10, the last spring frost in Grand Marais falls between May 7 and June 13, a 37-day window. The first fall frost falls between September 25 and October 27.
- The median last frost is 22 days later than the Michigan median of May 5.
- Its 136-day growing season is longer than 18% of the 878 Michigan places with a regular frost season (state median 162 days).
- The last frost is 26 days later than the zone 5b median of May 1. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 5b chart.
- The weather station records an average of 191 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 7 |
| 50% (median) | May 27 |
| 10% (safe for tender plants) | June 13 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 25 |
| 50% (median) | October 10 |
| 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 Grand Marais, MI
Grand Marais, MI frost dates — last frost May 27, first frost Oct 10, zone 5b. whenisthelastfrost.com
Crop
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Start indoors: Mar 4 to Mar 18Transplant outside: Apr 29 to May 13
Start indoors: Mar 18 to Apr 1Transplant outside: Jun 10 to Jun 24
Start indoors: Mar 18 to Apr 1Transplant outside: Jun 10 to Jun 24
Start indoors: Apr 1 to Apr 15Transplant outside: Jun 3 to Jun 17
Start indoors: Apr 1 to Apr 15Transplant outside: May 6 to May 20Sow outdoors: Apr 29 to Jun 3Plant for fall: Aug 15 to Sep 12
Start indoors: Apr 1 to Apr 15Transplant outside: Apr 29 to May 13Sow outdoors: Apr 29 to May 13Plant for fall: Aug 1 to Aug 22
Start indoors: Apr 1 to Apr 15Transplant outside: May 13 to May 27Plant for fall: Jul 4 to Jul 25
Start indoors: Apr 1 to Apr 15Transplant outside: May 6 to May 20Plant for fall: Jul 4 to Jul 25
Start indoors: Apr 1 to Apr 15Transplant outside: May 13 to May 27Plant for fall: Jul 4 to Jul 25
Start indoors: Apr 15 to Apr 29Transplant outside: Jun 17 to Jul 1Sow outdoors: Jun 17 to Jul 1
Start indoors: Apr 15 to Apr 29Transplant outside: Jun 3 to Jun 17
Sow outdoors: Apr 15 to May 6Plant for fall: Jul 18 to Aug 8
Sow outdoors: Apr 15 to May 6Plant for fall: Aug 15 to Sep 5
Sow outdoors: Apr 22 to Jun 3Plant for fall: Aug 29 to Sep 19
Start indoors: Apr 29 to May 6Transplant outside: Jun 10 to Jun 17Sow outdoors: Jun 3 to Jun 17Plant for fall: Jul 25 to Aug 8
Start indoors: Apr 29 to May 6Sow outdoors: Jun 3 to Jun 17Plant for fall: Aug 1 to Aug 15
Start indoors: Apr 29 to May 6Sow outdoors: Jun 3 to Jun 17
Start indoors: Apr 29 to May 6Transplant outside: Jun 10 to Jun 24
Sow outdoors: May 6 to Jun 3Plant for fall: Jul 18 to Aug 1
Sow outdoors: May 6 to Jun 3Plant for fall: Aug 1 to Aug 15
Sow outdoors: May 6 to May 27
Sow outdoors: May 13 to Jun 10Plant for fall: Aug 1 to Aug 15
Sow outdoors: May 13 to Jun 3Plant for fall: Aug 15 to Sep 5
Sow outdoors: Jun 3 to Jun 24Plant for fall: Jul 25 to Aug 8
Sow outdoors: Jun 3 to Jun 17
Transplant outside: Jun 10 to Jul 1
Plant for fall: Sep 26 to Oct 31
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Grand Marais, MI
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Mar 4 – Mar 18 | Apr 29 – May 13 | — | — |
| Peppers | Mar 18 – Apr 1 | Jun 10 – Jun 24 | — | — |
| Eggplant | Mar 18 – Apr 1 | Jun 10 – Jun 24 | — | — |
| Tomatoes | Apr 1 – Apr 15 | Jun 3 – Jun 17 | — | — |
| Lettuce | Apr 1 – Apr 15 | May 6 – May 20 | Apr 29 – Jun 3 | Aug 15 – Sep 12 |
| Kale | Apr 1 – Apr 15 | Apr 29 – May 13 | Apr 29 – May 13 | Aug 1 – Aug 22 |
| Broccoli | Apr 1 – Apr 15 | May 13 – May 27 | — | Jul 4 – Jul 25 |
| Cabbage | Apr 1 – Apr 15 | May 6 – May 20 | — | Jul 4 – Jul 25 |
| Cauliflower | Apr 1 – Apr 15 | May 13 – May 27 | — | Jul 4 – Jul 25 |
| Okra | Apr 15 – Apr 29 | Jun 17 – Jul 1 | Jun 17 – Jul 1 | — |
| Basil | Apr 15 – Apr 29 | Jun 3 – Jun 17 | — | — |
| Peas | — | — | Apr 15 – May 6 | Jul 18 – Aug 8 |
| Spinach | — | — | Apr 15 – May 6 | Aug 15 – Sep 5 |
| Radishes | — | — | Apr 22 – Jun 3 | Aug 29 – Sep 19 |
| Cucumbers | Apr 29 – May 6 | Jun 10 – Jun 17 | Jun 3 – Jun 17 | Jul 25 – Aug 8 |
| Zucchini & Summer Squash | Apr 29 – May 6 | — | Jun 3 – Jun 17 | Aug 1 – Aug 15 |
| Winter Squash & Pumpkins | Apr 29 – May 6 | — | Jun 3 – Jun 17 | — |
| Melons & Watermelon | Apr 29 – May 6 | Jun 10 – Jun 24 | — | — |
| Carrots | — | — | May 6 – Jun 3 | Jul 18 – Aug 1 |
| Beets | — | — | May 6 – Jun 3 | Aug 1 – Aug 15 |
| Potatoes | — | — | May 6 – May 27 | — |
| Swiss Chard | — | — | May 13 – Jun 10 | Aug 1 – Aug 15 |
| Cilantro | — | — | May 13 – Jun 3 | Aug 15 – Sep 5 |
| Green Beans | — | — | Jun 3 – Jun 24 | Jul 25 – Aug 8 |
| Sweet Corn | — | — | Jun 3 – Jun 17 | — |
| Sweet Potatoes | — | Jun 10 – Jul 1 | — | — |
| Garlic | — | — | — | Sep 26 – Oct 31 |
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 Grand Marais 2 E, MI weather station, 3 km away (elevation 623 ft (190 m)).
Frost dates near Grand Marais
- Seney May 27 · Oct 10
- Mc Millan May 21 · Oct 5
- Germfask May 26 · Sep 30
- Newberry May 21 · Oct 5
- Shingleton May 23 · Oct 10
- Curtis May 26 · Sep 30
- Engadine May 26 · Sep 30
- Wetmore May 16 · Oct 14
- Munising May 16 · Oct 14
- Gould City May 26 · Sep 30
Frequently asked questions
When is the last frost in Grand Marais, MI?
The median last spring frost in Grand Marais, MI is May 27. There is still about a 10% chance of frost after June 13, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Grand Marais, MI?
The median first fall frost is October 10, with about a 10% chance of frost before September 25.
How long is the growing season in Grand Marais, MI?
About 136 days between the median last spring frost and first fall frost.
What planting zone is Grand Marais, MI?
Grand Marais, MI is in USDA hardiness zone 5b.