When to plant in Onalaska, WI
USDA Zone 5aHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Onalaska, Wisconsin — all computed from Onalaska's nearest NOAA weather station.
In zone 5a, Onalaska gardeners can grow many hardy perennials, while the last and first frost still dictate the annual vegetable calendar.
The average first fall frost in Onalaska is now 6 days later than in the 1981–2010 normals. See how frost dates are shifting nationwide →
Frost probability
LA CROSSE MUNI AP · 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 Onalaska’s own odds, recorded at LA CROSSE MUNI AP.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 17 | May 4 | Apr 21 | Sep 24 | Oct 6 | Oct 21 |
| 32°F | May 6 | Apr 23 | Apr 9 | Oct 3 | Oct 17 | Nov 1 |
| 28°F | Apr 27 | Apr 12 | Mar 31 | Oct 15 | Oct 28 | Nov 11 |
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 Onalaska, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 9 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.
Onalaska planting FAQ
When is the last spring frost in Onalaska, WI?
On average, the last spring frost in Onalaska is around April 23 (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 Onalaska, WI?
In Onalaska, the first 32°F freeze of fall lands around October 17 on average. Time your last harvests and any season-extension cover before it.
What hardiness zone is Onalaska in?
Onalaska 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 Onalaska?
Onalaska has about 177 frost-free days — a moderate growing season — between the average last spring frost (April 23) and first fall frost (October 17).
When should I plant tomatoes in Onalaska?
For Onalaska, sow tomatoes indoors about February 26–March 12 and move the seedlings out around April 30, after the last spring frost.
Never miss a window in Onalaska
An email when it’s time to start seeds, transplant, and sow — timed to Onalaska’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- La Crosse · 7 km
- Holmen · 10 km
- Winona · 41 km
- Rochester · 103 km
- Reedsburg · 105 km
- Eau Claire · 106 km
- Chippewa Falls · 117 km
- Marshfield · 119 km
Frost dates recorded at LA CROSSE MUNI AP, 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 Onalaska, WI — Frost Dates & Zone 5a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USW00014920. Retrieved from https://blissgarden.com/wisconsin/onalaska.