When to plant in Owatonna, MN
USDA Zone 4bEverything below — frost dates, hardiness zone, and what to plant when in Owatonna, Minnesota — is derived from the closest NOAA station with complete climate normals.
Zone 4b is cold — in Owatonna, most perennials must be fully hardy, and your frost dates set a tight window for tender annual vegetables.
Frost probability
OWATONNA · 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 Owatonna’s own odds, recorded at OWATONNA.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 28 | May 14 | Apr 30 | Sep 15 | Sep 29 | Oct 11 |
| 32°F | May 20 | May 5 | Apr 20 | Sep 23 | Oct 6 | Oct 21 |
| 28°F | May 12 | Apr 25 | Apr 10 | Oct 2 | Oct 18 | Nov 1 |
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 Owatonna, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 24 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.
Owatonna planting FAQ
When is the last spring frost in Owatonna, MN?
Plan for the last spring frost in Owatonna around May 5 (the date it has a 50% chance of a 32°F freeze). Anything frost-sensitive should go out after it.
When is the first fall frost in Owatonna, MN?
In Owatonna, the first 32°F freeze of fall lands around October 6 on average. Time your last harvests and any season-extension cover before it.
What hardiness zone is Owatonna in?
Owatonna 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 Owatonna?
There are roughly 154 frost-free days in Owatonna (a moderate growing season), running from the average last frost around May 5 to the first fall frost near October 6.
When should I plant tomatoes in Owatonna?
In Owatonna, start tomato seeds indoors around March 10–March 24, then transplant seedlings outdoors around May 12 once the danger of frost has passed.
Never miss a window in Owatonna
An email when it’s time to start seeds, transplant, and sow — timed to Owatonna’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Faribault · 23 km
- Northfield · 41 km
- Albert Lea · 50 km
- Austin · 51 km
- Mankato · 60 km
- Rochester · 61 km
- Farmington · 63 km
- St. Peter · 64 km
Frost dates recorded at OWATONNA, 1 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 Owatonna, MN — Frost Dates & Zone 4b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00216287. Retrieved from https://blissgarden.com/minnesota/owatonna.