When to plant in Middleton, WI
USDA Zone 5aHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Middleton, Wisconsin — all computed from Middleton's nearest NOAA weather station.
Zone 5a means Middleton sees real winter cold, but a good range of perennials survive; the frost dates above govern when annual vegetables go out.
The average last spring frost in Middleton is now 6 days later than in the 1981–2010 normals. See how frost dates are shifting nationwide →
Frost probability
CHARMANY FARM · 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 Middleton’s own odds, recorded at CHARMANY FARM.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 22 | May 7 | Apr 25 | Sep 20 | Oct 4 | Oct 17 |
| 32°F | May 11 | Apr 28 | Apr 14 | Sep 29 | Oct 15 | Oct 29 |
| 28°F | May 1 | Apr 17 | Apr 4 | Oct 10 | 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 Middleton, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 14 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.
Middleton planting FAQ
When is the last spring frost in Middleton, WI?
Middleton's average last spring frost falls near April 28 — the 50% mark at 32°F in the 1991–2020 normals. Hold tender transplants until the risk has passed, then plant out.
When is the first fall frost in Middleton, WI?
The first fall frost in Middleton typically arrives around October 15 (50% probability at 32°F). Harvest or protect frost-sensitive crops before then.
What hardiness zone is Middleton in?
Middleton 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 Middleton?
There are roughly 170 frost-free days in Middleton (a moderate growing season), running from the average last frost around April 28 to the first fall frost near October 15.
When should I plant tomatoes in Middleton?
In Middleton, start tomato seeds indoors around March 3–March 17, then transplant seedlings outdoors around May 5 once the danger of frost has passed.
Never miss a window in Middleton
An email when it’s time to start seeds, transplant, and sow — timed to Middleton’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reachFrost dates recorded at CHARMANY FARM, 6 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 Middleton, WI — Frost Dates & Zone 5a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00471416. Retrieved from https://blissgarden.com/wisconsin/middleton.