When to plant in Fort Madison, IA
USDA Zone 6aHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Fort Madison, Iowa — all computed from Fort Madison's nearest NOAA weather station.
Zone 6a means Fort Madison sees real winter cold, but a good range of perennials survive; the frost dates above govern when annual vegetables go out.
Frost probability
FT MADISON · 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 Fort Madison’s own odds, recorded at FT MADISON.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 7 | Apr 24 | Apr 10 | Oct 1 | Oct 16 | Oct 27 |
| 32°F | Apr 26 | Apr 12 | Apr 1 | Oct 11 | Oct 25 | Nov 6 |
| 28°F | Apr 17 | Apr 3 | Mar 18 | Oct 23 | Nov 4 | Nov 18 |
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 Fort Madison, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 25 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.
Fort Madison planting FAQ
When is the last spring frost in Fort Madison, IA?
On average, the last spring frost in Fort Madison is around April 12 (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 Fort Madison, IA?
The first fall frost in Fort Madison typically arrives around October 25 (50% probability at 32°F). Harvest or protect frost-sensitive crops before then.
What hardiness zone is Fort Madison in?
Fort Madison is in USDA hardiness zone 6a. In zone 6a, winters are moderate — most common vegetables grow well in season.
How long is the growing season in Fort Madison?
There are roughly 196 frost-free days in Fort Madison (a moderate growing season), running from the average last frost around April 12 to the first fall frost near October 25.
When should I plant tomatoes in Fort Madison?
In Fort Madison, start tomato seeds indoors around February 15–March 1, then transplant seedlings outdoors around April 19 once the danger of frost has passed.
Never miss a window in Fort Madison
An email when it’s time to start seeds, transplant, and sow — timed to Fort Madison’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reachFrost dates recorded at FT MADISON, 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 Fort Madison, IA — Frost Dates & Zone 6a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00133007. Retrieved from https://blissgarden.com/iowa/fort-madison.