When to plant in Willmar, MN
USDA Zone 4bHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Willmar, Minnesota — all computed from Willmar's nearest NOAA weather station.
In zone 4b, Willmar winters are severe; choose cold-hardy perennials and time annuals carefully around the frost dates above.
Frost probability
WILLMAR 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 Willmar’s own odds, recorded at WILLMAR WWTP.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 23 | May 9 | Apr 27 | Sep 16 | Sep 29 | Oct 11 |
| 32°F | May 13 | Apr 30 | Apr 16 | Sep 23 | Oct 7 | Oct 21 |
| 28°F | May 2 | Apr 19 | Apr 5 | Oct 2 | Oct 19 | Oct 31 |
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 Willmar, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 22 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.
Willmar planting FAQ
When is the last spring frost in Willmar, MN?
On average, the last spring frost in Willmar 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 Willmar, MN?
The first fall frost in Willmar typically arrives around October 7 (50% probability at 32°F). Harvest or protect frost-sensitive crops before then.
What hardiness zone is Willmar in?
Willmar is in USDA hardiness zone 4b. In zone 4b, winters are cold — pick cold-hardy varieties and protect tender crops.
How long is the growing season in Willmar?
Willmar has about 160 frost-free days — a moderate growing season — between the average last spring frost (April 30) and first fall frost (October 7).
When should I plant tomatoes in Willmar?
For Willmar, 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 Willmar
An email when it’s time to start seeds, transplant, and sow — timed to Willmar’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Hutchinson · 60 km
- St. Cloud · 83 km
- Sartell · 86 km
- Alexandria · 88 km
- Sauk Rapids · 88 km
- Buffalo · 94 km
- Marshall · 94 km
- New Ulm · 101 km
Frost dates recorded at WILLMAR 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 Willmar, MN — Frost Dates & Zone 4b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00219004. Retrieved from https://blissgarden.com/minnesota/willmar.