When to plant in Watertown, WI
USDA Zone 5bWatertown, Wisconsin frost dates, USDA zone, and a full-year planting calendar, drawn from the nearest NOAA station and tuned to the local season.
In zone 5b, Watertown gardeners can grow many hardy perennials, while the last and first frost still dictate the annual vegetable calendar.
Frost probability
WATERTOWN 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 Watertown’s own odds, recorded at WATERTOWN WWTP.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 24 | May 9 | Apr 25 | Sep 20 | Oct 2 | Oct 15 |
| 32°F | May 13 | Apr 28 | Apr 14 | Sep 28 | Oct 12 | Oct 27 |
| 28°F | Apr 30 | Apr 16 | Apr 3 | Oct 8 | Oct 25 | 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 Watertown, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 20 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.
Watertown planting FAQ
When is the last spring frost in Watertown, WI?
On average, the last spring frost in Watertown is around April 28 (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 Watertown, WI?
Expect Watertown's first fall frost near October 12 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.
What hardiness zone is Watertown in?
Watertown 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 Watertown?
Watertown has about 167 frost-free days — a moderate growing season — between the average last spring frost (April 28) and first fall frost (October 12).
When should I plant tomatoes in Watertown?
For Watertown, sow tomatoes indoors about March 3–March 17 and move the seedlings out around May 5, after the last spring frost.
Never miss a window in Watertown
An email when it’s time to start seeds, transplant, and sow — timed to Watertown’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Oconomowoc · 21 km
- Fort Atkinson · 31 km
- Hartford · 32 km
- Beaver Dam · 33 km
- Lisbon · 39 km
- Whitewater · 39 km
- Richfield · 40 km
- Sussex · 41 km
Frost dates recorded at WATERTOWN WWTP, 2 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 Watertown, WI — Frost Dates & Zone 5b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00478919. Retrieved from https://blissgarden.com/wisconsin/watertown.