When to plant in Green Bay, WI
USDA Zone 5bHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Green Bay, Wisconsin — all computed from Green Bay's nearest NOAA weather station.
In zone 5b, Green Bay gardeners can grow many hardy perennials, while the last and first frost still dictate the annual vegetable calendar.
Frost probability
GREEN BAY BOTANICAL · 1991–2020The date the last spring and first fall frost occur, by threshold and probability. A 90% date is later in spring — and earlier in fall — than a 10% date; the 50% · 32°F row is what most gardeners plan around. These are Green Bay’s own odds, recorded at GREEN BAY BOTANICAL.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 31 | May 19 | May 4 | Sep 15 | Sep 28 | Oct 12 |
| 32°F | May 22 | May 7 | Apr 24 | Sep 23 | Oct 9 | Oct 25 |
| 28°F | May 12 | Apr 27 | Apr 10 | Oct 5 | Oct 25 | Nov 7 |
Download this table as CSV ↓ — every threshold and probability, plus this city’s planting-window dates.
What to plant now
TODAY · JULY 19Full-year planting calendar
Each bar is the exact window to take a planting action in Green Bay, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 10 km · complete 32°F normalsWhen stations disagree by more than a few days, that spread is real microclimate variation — elevation, water, urban heat. Judge which station best matches your own yard.
Green Bay planting FAQ
When is the last spring frost in Green Bay, WI?
Plan for the last spring frost in Green Bay around May 7 (the date it has a 50% chance of a 32°F freeze). Anything frost-sensitive should go out after it.
When is the first fall frost in Green Bay, WI?
Expect Green Bay's first fall frost near October 9 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.
What hardiness zone is Green Bay in?
Green Bay is in USDA hardiness zone 5b. In zone 5b, winters are cold — pick cold-hardy varieties and protect tender crops.
How long is the growing season in Green Bay?
Green Bay has about 155 frost-free days — a moderate growing season — between the average last spring frost (May 7) and first fall frost (October 9).
When should I plant tomatoes in Green Bay?
For Green Bay, sow tomatoes indoors about March 12–March 26 and move the seedlings out around May 14, after the last spring frost.
Never miss a window in Green Bay
An email when it’s time to start seeds, transplant, and sow — timed to Green Bay’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reachFrost dates recorded at GREEN BAY BOTANICAL, 9 km from the city center · 1991–2020 NOAA climate normals · zone from the USDA/PRISM 2023 map. How we compute this.
BlissGarden. "When to Plant in Green Bay, WI — Frost Dates & Zone 5b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00473271. Retrieved from https://blissgarden.com/wisconsin/green-bay.