When to plant in Superior, WI
USDA Zone 5aEverything below — frost dates, hardiness zone, and what to plant when in Superior, Wisconsin — is derived from the closest NOAA station with complete climate normals.
In zone 5a, Superior gardeners can grow many hardy perennials, while the last and first frost still dictate the annual vegetable calendar.
Frost probability
SUPERIOR · 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 Superior’s own odds, recorded at SUPERIOR.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Jun 8 | May 21 | May 6 | Sep 15 | Sep 28 | Oct 11 |
| 32°F | May 25 | May 6 | Apr 24 | Sep 24 | Oct 9 | Oct 24 |
| 28°F | May 9 | Apr 24 | Apr 10 | Oct 6 | Oct 24 | 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 Superior, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 17 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.
Superior planting FAQ
When is the last spring frost in Superior, WI?
Plan for the last spring frost in Superior around May 6 (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 Superior, WI?
Expect Superior's first fall frost near October 9 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.
What hardiness zone is Superior in?
Superior is in USDA hardiness zone 5a. In zone 5a, winters are cold — pick cold-hardy varieties and protect tender crops.
How long is the growing season in Superior?
Superior has about 156 frost-free days — a moderate growing season — between the average last spring frost (May 6) and first fall frost (October 9).
When should I plant tomatoes in Superior?
For Superior, sow tomatoes indoors about March 11–March 25 and move the seedlings out around May 13, after the last spring frost.
Never miss a window in Superior
An email when it’s time to start seeds, transplant, and sow — timed to Superior’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Duluth · 10 km
- Hermantown · 17 km
- Cloquet · 32 km
- Hibbing · 102 km
- Grand Rapids · 126 km
- North Branch · 148 km
- Cambridge · 154 km
- Brainerd · 166 km
Frost dates recorded at SUPERIOR, 4 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 Superior, WI — Frost Dates & Zone 5a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00478349. Retrieved from https://blissgarden.com/wisconsin/superior.