When to plant in Monroe, WI
USDA Zone 5aHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Monroe, Wisconsin — all computed from Monroe's nearest NOAA weather station.
In zone 5a, Monroe gardeners can grow many hardy perennials, while the last and first frost still dictate the annual vegetable calendar.
Frost probability
MONROE 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 Monroe’s own odds, recorded at MONROE WWTP.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 22 | May 6 | Apr 23 | Sep 21 | Oct 4 | Oct 17 |
| 32°F | May 12 | Apr 27 | Apr 12 | Sep 29 | Oct 14 | Oct 29 |
| 28°F | May 1 | Apr 15 | Apr 2 | Oct 9 | Oct 25 | 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 Monroe, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 34 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.
Monroe planting FAQ
When is the last spring frost in Monroe, WI?
Monroe's average last spring frost falls near April 27 — 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 Monroe, WI?
In Monroe, the first 32°F freeze of fall lands around October 14 on average. Time your last harvests and any season-extension cover before it.
What hardiness zone is Monroe in?
Monroe 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 Monroe?
Monroe has about 170 frost-free days — a moderate growing season — between the average last spring frost (April 27) and first fall frost (October 14).
When should I plant tomatoes in Monroe?
For Monroe, sow tomatoes indoors about March 2–March 16 and move the seedlings out around May 4, after the last spring frost.
Never miss a window in Monroe
An email when it’s time to start seeds, transplant, and sow — timed to Monroe’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reachFrost dates recorded at MONROE WWTP, 3 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 Monroe, WI — Frost Dates & Zone 5a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00475573. Retrieved from https://blissgarden.com/wisconsin/monroe.