When to plant in Greenfield, WI
USDA Zone 5bEverything below — frost dates, hardiness zone, and what to plant when in Greenfield, Wisconsin — is derived from the closest NOAA station with complete climate normals.
Zone 5b means Greenfield sees real winter cold, but a good range of perennials survive; the frost dates above govern when annual vegetables go out.
Frost probability
HALES CORNERS/WHITNALL PARK/BO · 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 Greenfield’s own odds, recorded at HALES CORNERS/WHITNALL PARK/BO.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 29 | May 14 | Apr 30 | Sep 22 | Oct 3 | Oct 15 |
| 32°F | May 19 | May 3 | Apr 18 | Sep 30 | Oct 14 | Oct 26 |
| 28°F | May 9 | Apr 21 | Apr 8 | Oct 8 | Oct 24 | Nov 6 |
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 Greenfield, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 8 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.
Greenfield planting FAQ
When is the last spring frost in Greenfield, WI?
On average, the last spring frost in Greenfield is around May 3 (50% probability at 32°F, from 1991–2020 NOAA normals). Wait until after this date to set out tender plants like tomatoes and peppers.
When is the first fall frost in Greenfield, WI?
The first fall frost in Greenfield typically arrives around October 14 (50% probability at 32°F). Harvest or protect frost-sensitive crops before then.
What hardiness zone is Greenfield in?
Greenfield 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 Greenfield?
There are roughly 164 frost-free days in Greenfield (a moderate growing season), running from the average last frost around May 3 to the first fall frost near October 14.
When should I plant tomatoes in Greenfield?
In Greenfield, start tomato seeds indoors around March 8–March 22, then transplant seedlings outdoors around May 10 once the danger of frost has passed.
Never miss a window in Greenfield
An email when it’s time to start seeds, transplant, and sow — timed to Greenfield’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Greendale · 2 km
- West Allis · 6 km
- Franklin · 9 km
- New Berlin · 10 km
- Cudahy · 12 km
- Wauwatosa · 12 km
- Milwaukee · 12 km
- Oak Creek · 13 km
Frost dates recorded at HALES CORNERS/WHITNALL PARK/BO, 3 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 Greenfield, WI — Frost Dates & Zone 5b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00473391. Retrieved from https://blissgarden.com/wisconsin/greenfield.