Washington Island, WI frost dates
Last spring frostMay 15median date
First fall frostOct 14median date
Growing season152 daysfrost-free
Hardiness zone6aZone 6a
How Washington Island compares
- In 8 years out of 10, the last spring frost in Washington Island falls between April 30 and May 31, a 31-day window. The first fall frost falls between September 28 and October 31.
- The median last frost is 10 days later than the Wisconsin median of May 5.
- Its 152-day growing season is longer than 42% of the 749 Wisconsin places with a regular frost season (state median 155 days).
- The last frost is 16 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 149 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 30 |
| 50% (median) | May 15 |
| 10% (safe for tender plants) | May 31 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 28 |
| 50% (median) | October 14 |
| 90% (late) | October 31 |
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 Washington Island, WI
Washington Island, WI frost dates — last frost May 15, first frost Oct 14, zone 6a. whenisthelastfrost.com
Crop
JFMAMJJASOND
Start indoors: Feb 20 to Mar 6Transplant outside: Apr 17 to May 1
Start indoors: Mar 6 to Mar 20Transplant outside: May 29 to Jun 12
Start indoors: Mar 6 to Mar 20Transplant outside: May 29 to Jun 12
Start indoors: Mar 20 to Apr 3Transplant outside: May 22 to Jun 5
Start indoors: Mar 20 to Apr 3Transplant outside: Apr 24 to May 8Sow outdoors: Apr 17 to May 22Plant for fall: Aug 19 to Sep 16
Start indoors: Mar 20 to Apr 3Transplant outside: Apr 17 to May 1Sow outdoors: Apr 17 to May 1Plant for fall: Aug 5 to Aug 26
Start indoors: Mar 20 to Apr 3Transplant outside: May 1 to May 15Plant for fall: Jul 8 to Jul 29
Start indoors: Mar 20 to Apr 3Transplant outside: Apr 24 to May 8Plant for fall: Jul 8 to Jul 29
Start indoors: Mar 20 to Apr 3Transplant outside: May 1 to May 15Plant for fall: Jul 8 to Jul 29
Start indoors: Apr 3 to Apr 17Transplant outside: Jun 5 to Jun 19Sow outdoors: Jun 5 to Jun 19
Start indoors: Apr 3 to Apr 17Transplant outside: May 22 to Jun 5
Sow outdoors: Apr 3 to Apr 24Plant for fall: Jul 22 to Aug 12
Sow outdoors: Apr 3 to Apr 24Plant for fall: Aug 19 to Sep 9
Sow outdoors: Apr 10 to May 22Plant for fall: Sep 2 to Sep 23
Start indoors: Apr 17 to Apr 24Transplant outside: May 29 to Jun 5Sow outdoors: May 22 to Jun 5Plant for fall: Jul 29 to Aug 12
Start indoors: Apr 17 to Apr 24Sow outdoors: May 22 to Jun 5Plant for fall: Aug 5 to Aug 19
Start indoors: Apr 17 to Apr 24Sow outdoors: May 22 to Jun 5
Start indoors: Apr 17 to Apr 24Transplant outside: May 29 to Jun 12
Sow outdoors: Apr 24 to May 22Plant for fall: Jul 22 to Aug 5
Sow outdoors: Apr 24 to May 22Plant for fall: Aug 5 to Aug 19
Sow outdoors: Apr 24 to May 15
Sow outdoors: May 1 to May 29Plant for fall: Aug 5 to Aug 19
Sow outdoors: May 1 to May 22Plant for fall: Aug 19 to Sep 9
Sow outdoors: May 22 to Jun 12Plant for fall: Jul 29 to Aug 12
Sow outdoors: May 22 to Jun 5
Transplant outside: May 29 to Jun 19
Plant for fall: Sep 30 to Nov 4
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Washington Island, WI
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 20 – Mar 6 | Apr 17 – May 1 | — | — |
| Peppers | Mar 6 – Mar 20 | May 29 – Jun 12 | — | — |
| Eggplant | Mar 6 – Mar 20 | May 29 – Jun 12 | — | — |
| Tomatoes | Mar 20 – Apr 3 | May 22 – Jun 5 | — | — |
| Lettuce | Mar 20 – Apr 3 | Apr 24 – May 8 | Apr 17 – May 22 | Aug 19 – Sep 16 |
| Kale | Mar 20 – Apr 3 | Apr 17 – May 1 | Apr 17 – May 1 | Aug 5 – Aug 26 |
| Broccoli | Mar 20 – Apr 3 | May 1 – May 15 | — | Jul 8 – Jul 29 |
| Cabbage | Mar 20 – Apr 3 | Apr 24 – May 8 | — | Jul 8 – Jul 29 |
| Cauliflower | Mar 20 – Apr 3 | May 1 – May 15 | — | Jul 8 – Jul 29 |
| Okra | Apr 3 – Apr 17 | Jun 5 – Jun 19 | Jun 5 – Jun 19 | — |
| Basil | Apr 3 – Apr 17 | May 22 – Jun 5 | — | — |
| Peas | — | — | Apr 3 – Apr 24 | Jul 22 – Aug 12 |
| Spinach | — | — | Apr 3 – Apr 24 | Aug 19 – Sep 9 |
| Radishes | — | — | Apr 10 – May 22 | Sep 2 – Sep 23 |
| Cucumbers | Apr 17 – Apr 24 | May 29 – Jun 5 | May 22 – Jun 5 | Jul 29 – Aug 12 |
| Zucchini & Summer Squash | Apr 17 – Apr 24 | — | May 22 – Jun 5 | Aug 5 – Aug 19 |
| Winter Squash & Pumpkins | Apr 17 – Apr 24 | — | May 22 – Jun 5 | — |
| Melons & Watermelon | Apr 17 – Apr 24 | May 29 – Jun 12 | — | — |
| Carrots | — | — | Apr 24 – May 22 | Jul 22 – Aug 5 |
| Beets | — | — | Apr 24 – May 22 | Aug 5 – Aug 19 |
| Potatoes | — | — | Apr 24 – May 15 | — |
| Swiss Chard | — | — | May 1 – May 29 | Aug 5 – Aug 19 |
| Cilantro | — | — | May 1 – May 22 | Aug 19 – Sep 9 |
| Green Beans | — | — | May 22 – Jun 12 | Jul 29 – Aug 12 |
| Sweet Corn | — | — | May 22 – Jun 5 | — |
| Sweet Potatoes | — | May 29 – Jun 19 | — | — |
| Garlic | — | — | — | Sep 30 – Nov 4 |
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 Washington Is, WI weather station, 2 km away (elevation 686 ft (209 m)).
Frost dates near Washington Island
- Ellison Bay May 14 · Oct 18
- Sister Bay May 14 · Oct 18
- Ephraim May 14 · Oct 18
- Fish Creek May 14 · Oct 18
- Baileys Harbor May 14 · Oct 18
- Egg Harbor May 8 · Oct 13
- Marinette May 4 · Oct 11
- Sturgeon Bay May 8 · Oct 13
- Porterfield May 4 · Oct 11
- Wausaukee May 22 · Sep 27
Frequently asked questions
When is the last frost in Washington Island, WI?
The median last spring frost in Washington Island, WI is May 15. There is still about a 10% chance of frost after May 31, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Washington Island, WI?
The median first fall frost is October 14, with about a 10% chance of frost before September 28.
How long is the growing season in Washington Island, WI?
About 152 days between the median last spring frost and first fall frost.
What planting zone is Washington Island, WI?
Washington Island, WI is in USDA hardiness zone 6a.