When to plant in Brookfield, WI
USDA Zone 5bEverything below — frost dates, hardiness zone, and what to plant when in Brookfield, Wisconsin — is derived from the closest NOAA station with complete climate normals.
In zone 5b, Brookfield gardeners can grow many hardy perennials, while the last and first frost still dictate the annual vegetable calendar.
Frost probability
BROOKFIELD WWTP · 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 Brookfield’s own odds, recorded at BROOKFIELD WWTP.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 29 | May 10 | Apr 28 | Sep 21 | Oct 3 | Oct 17 |
| 32°F | May 15 | Apr 30 | Apr 16 | Sep 28 | Oct 14 | Oct 27 |
| 28°F | May 3 | Apr 19 | Apr 5 | Oct 10 | 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 Brookfield, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 11 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.
Brookfield planting FAQ
When is the last spring frost in Brookfield, WI?
On average, the last spring frost in Brookfield is around April 30 (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 Brookfield, WI?
The first fall frost in Brookfield typically arrives around October 14 (50% probability at 32°F). Harvest or protect frost-sensitive crops before then.
What hardiness zone is Brookfield in?
Brookfield 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 Brookfield?
Brookfield has about 167 frost-free days — a moderate growing season — between the average last spring frost (April 30) and first fall frost (October 14).
When should I plant tomatoes in Brookfield?
For Brookfield, sow tomatoes indoors about March 5–March 19 and move the seedlings out around May 7, after the last spring frost.
Never miss a window in Brookfield
An email when it’s time to start seeds, transplant, and sow — timed to Brookfield’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Wauwatosa · 7 km
- West Allis · 10 km
- Pewaukee · 10 km
- New Berlin · 10 km
- Menomonee Falls · 11 km
- Sussex · 12 km
- Waukesha · 12 km
- Milwaukee · 12 km
Frost dates recorded at BROOKFIELD WWTP, 5 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 Brookfield, WI — Frost Dates & Zone 5b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00471062. Retrieved from https://blissgarden.com/wisconsin/brookfield.