When to plant in Sussex, WI
USDA Zone 5bSussex, Wisconsin frost dates, USDA zone, and a full-year planting calendar, drawn from the nearest NOAA station and tuned to the local season.
Zone 5b means Sussex sees real winter cold, but a good range of perennials survive; the frost dates above govern when annual vegetables go out.
Frost probability
RICHFIELD 3 SSW · 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 Sussex’s own odds, recorded at RICHFIELD 3 SSW.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 28 | May 12 | Apr 28 | Sep 22 | Oct 4 | Oct 17 |
| 32°F | May 16 | Apr 30 | Apr 16 | Oct 1 | Oct 16 | Oct 29 |
| 28°F | May 4 | Apr 19 | Apr 5 | Oct 11 | Oct 27 | Nov 10 |
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 Sussex, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 14 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.
Sussex planting FAQ
When is the last spring frost in Sussex, WI?
On average, the last spring frost in Sussex 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 Sussex, WI?
Expect Sussex's first fall frost near October 16 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.
What hardiness zone is Sussex in?
Sussex 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 Sussex?
There are roughly 169 frost-free days in Sussex (a moderate growing season), running from the average last frost around April 30 to the first fall frost near October 16.
When should I plant tomatoes in Sussex?
In Sussex, start tomato seeds indoors around March 5–March 19, then transplant seedlings outdoors around May 7 once the danger of frost has passed.
Never miss a window in Sussex
An email when it’s time to start seeds, transplant, and sow — timed to Sussex’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Lisbon · 3 km
- Pewaukee · 8 km
- Menomonee Falls · 9 km
- Richfield · 12 km
- Brookfield · 12 km
- Germantown · 14 km
- Waukesha · 14 km
- Wauwatosa · 17 km
Frost dates recorded at RICHFIELD 3 SSW, 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 Sussex, WI — Frost Dates & Zone 5b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00477148. Retrieved from https://blissgarden.com/wisconsin/sussex.