Marengo, WI frost dates
Last spring frostMay 26median date
First fall frostSep 27median date
Growing season124 daysfrost-free
Hardiness zone4bZone 4b
How Marengo compares
- In 8 years out of 10, the last spring frost in Marengo falls between May 8 and June 9, a 32-day window. The first fall frost falls between September 12 and October 11.
- The median last frost is 21 days later than the Wisconsin median of May 5.
- Its 124-day growing season is longer than 4% of the 749 Wisconsin places with a regular frost season (state median 155 days).
- The last frost is 18 days later than the zone 4b median of May 8. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 4b chart.
- The weather station records an average of 190 nights a year at or below 32°F.
- Compared with Duluth, MN, 107 km away, the last frost here is 12 days later than there and the growing season is 27 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 8 |
| 50% (median) | May 26 |
| 10% (safe for tender plants) | June 9 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 12 |
| 50% (median) | September 27 |
| 90% (late) | October 11 |
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 Marengo, WI
Marengo, WI frost dates — last frost May 26, first frost Sep 27, zone 4b. whenisthelastfrost.com
Crop
JFMAMJJASOND
Start indoors: Mar 3 to Mar 17Transplant outside: Apr 28 to May 12
Start indoors: Mar 17 to Mar 31Transplant outside: Jun 9 to Jun 23
Start indoors: Mar 17 to Mar 31Transplant outside: Jun 9 to Jun 23
Start indoors: Mar 31 to Apr 14Transplant outside: Jun 2 to Jun 16
Start indoors: Mar 31 to Apr 14Transplant outside: May 5 to May 19Sow outdoors: Apr 28 to Jun 2Plant for fall: Aug 2 to Aug 30
Start indoors: Mar 31 to Apr 14Transplant outside: Apr 28 to May 12Sow outdoors: Apr 28 to May 12Plant for fall: Jul 19 to Aug 9
Start indoors: Mar 31 to Apr 14Transplant outside: May 12 to May 26Plant for fall: Jun 21 to Jul 12
Start indoors: Mar 31 to Apr 14Transplant outside: May 5 to May 19Plant for fall: Jun 21 to Jul 12
Start indoors: Mar 31 to Apr 14Transplant outside: May 12 to May 26Plant for fall: Jun 21 to Jul 12
Start indoors: Apr 14 to Apr 28Transplant outside: Jun 16 to Jun 30Sow outdoors: Jun 16 to Jun 30
Start indoors: Apr 14 to Apr 28Transplant outside: Jun 2 to Jun 16
Sow outdoors: Apr 14 to May 5Plant for fall: Jul 5 to Jul 26
Sow outdoors: Apr 14 to May 5Plant for fall: Aug 2 to Aug 23
Sow outdoors: Apr 21 to Jun 2Plant for fall: Aug 16 to Sep 6
Start indoors: Apr 28 to May 5Transplant outside: Jun 9 to Jun 16Sow outdoors: Jun 2 to Jun 16Plant for fall: Jul 12 to Jul 26
Start indoors: Apr 28 to May 5Sow outdoors: Jun 2 to Jun 16Plant for fall: Jul 19 to Aug 2
Start indoors: Apr 28 to May 5Sow outdoors: Jun 2 to Jun 16
Start indoors: Apr 28 to May 5Transplant outside: Jun 9 to Jun 23
Sow outdoors: May 5 to Jun 2Plant for fall: Jul 5 to Jul 19
Sow outdoors: May 5 to Jun 2Plant for fall: Jul 19 to Aug 2
Sow outdoors: May 5 to May 26
Sow outdoors: May 12 to Jun 9Plant for fall: Jul 19 to Aug 2
Sow outdoors: May 12 to Jun 2Plant for fall: Aug 2 to Aug 23
Sow outdoors: Jun 2 to Jun 23Plant for fall: Jul 12 to Jul 26
Sow outdoors: Jun 2 to Jun 16
Transplant outside: Jun 9 to Jun 30
Plant for fall: Sep 13 to Oct 18
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Marengo, WI
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Mar 3 – Mar 17 | Apr 28 – May 12 | — | — |
| Peppers | Mar 17 – Mar 31 | Jun 9 – Jun 23 | — | — |
| Eggplant | Mar 17 – Mar 31 | Jun 9 – Jun 23 | — | — |
| Tomatoes | Mar 31 – Apr 14 | Jun 2 – Jun 16 | — | — |
| Lettuce | Mar 31 – Apr 14 | May 5 – May 19 | Apr 28 – Jun 2 | Aug 2 – Aug 30 |
| Kale | Mar 31 – Apr 14 | Apr 28 – May 12 | Apr 28 – May 12 | Jul 19 – Aug 9 |
| Broccoli | Mar 31 – Apr 14 | May 12 – May 26 | — | Jun 21 – Jul 12 |
| Cabbage | Mar 31 – Apr 14 | May 5 – May 19 | — | Jun 21 – Jul 12 |
| Cauliflower | Mar 31 – Apr 14 | May 12 – May 26 | — | Jun 21 – Jul 12 |
| Okra | Apr 14 – Apr 28 | Jun 16 – Jun 30 | Jun 16 – Jun 30 | — |
| Basil | Apr 14 – Apr 28 | Jun 2 – Jun 16 | — | — |
| Peas | — | — | Apr 14 – May 5 | Jul 5 – Jul 26 |
| Spinach | — | — | Apr 14 – May 5 | Aug 2 – Aug 23 |
| Radishes | — | — | Apr 21 – Jun 2 | Aug 16 – Sep 6 |
| Cucumbers | Apr 28 – May 5 | Jun 9 – Jun 16 | Jun 2 – Jun 16 | Jul 12 – Jul 26 |
| Zucchini & Summer Squash | Apr 28 – May 5 | — | Jun 2 – Jun 16 | Jul 19 – Aug 2 |
| Winter Squash & Pumpkins | Apr 28 – May 5 | — | Jun 2 – Jun 16 | — |
| Melons & Watermelon | Apr 28 – May 5 | Jun 9 – Jun 23 | — | — |
| Carrots | — | — | May 5 – Jun 2 | Jul 5 – Jul 19 |
| Beets | — | — | May 5 – Jun 2 | Jul 19 – Aug 2 |
| Potatoes | — | — | May 5 – May 26 | — |
| Swiss Chard | — | — | May 12 – Jun 9 | Jul 19 – Aug 2 |
| Cilantro | — | — | May 12 – Jun 2 | Aug 2 – Aug 23 |
| Green Beans | — | — | Jun 2 – Jun 23 | Jul 12 – Jul 26 |
| Sweet Corn | — | — | Jun 2 – Jun 16 | — |
| Sweet Potatoes | — | Jun 9 – Jun 30 | — | — |
| Garlic | — | — | — | Sep 13 – Oct 18 |
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 Mellen 4 Ne, WI weather station, 16 km away (elevation 1,299 ft (396 m)).
Frost dates near Marengo
- High Bridge May 26 · Sep 27
- Mellen May 26 · Sep 27
- Ashland May 20 · Oct 2
- Benoit May 23 · Sep 29
- Grand View May 20 · Oct 1
- Mason May 20 · Oct 1
- Odanah May 23 · Oct 1
- Clam Lake May 16 · Sep 30
- Washburn May 23 · Oct 2
- Saxon May 23 · Oct 1
Frequently asked questions
When is the last frost in Marengo, WI?
The median last spring frost in Marengo, WI is May 26. There is still about a 10% chance of frost after June 9, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Marengo, WI?
The median first fall frost is September 27, with about a 10% chance of frost before September 12.
How long is the growing season in Marengo, WI?
About 124 days between the median last spring frost and first fall frost.
What planting zone is Marengo, WI?
Marengo, WI is in USDA hardiness zone 4b.