When to plant in Iowa City, IA
USDA Zone 5bIowa City, Iowa frost dates, USDA zone, and a full-year planting calendar, drawn from the nearest NOAA station and tuned to the local season.
In zone 5b, Iowa City gardeners can grow many hardy perennials, while the last and first frost still dictate the annual vegetable calendar.
The average first fall frost in Iowa City is now 7 days later than in the 1981–2010 normals. See how frost dates are shifting nationwide →
Frost probability
IOWA CITY 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 Iowa City’s own odds, recorded at IOWA CITY MUNI AP.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 15 | May 1 | Apr 17 | Sep 26 | Oct 9 | Oct 21 |
| 32°F | May 6 | Apr 21 | Apr 5 | Oct 4 | Oct 18 | Oct 31 |
| 28°F | Apr 27 | Apr 9 | Mar 25 | Oct 15 | Oct 28 | Nov 9 |
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 Iowa City, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 30 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.
Iowa City planting FAQ
When is the last spring frost in Iowa City, IA?
Plan for the last spring frost in Iowa City around April 21 (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 Iowa City, IA?
In Iowa City, the first 32°F freeze of fall lands around October 18 on average. Time your last harvests and any season-extension cover before it.
What hardiness zone is Iowa City in?
Iowa City is in USDA hardiness zone 5b. In zone 5b, winters are cold — pick cold-hardy varieties and protect tender crops.
How long is the growing season in Iowa City?
Iowa City has about 180 frost-free days — a moderate growing season — between the average last spring frost (April 21) and first fall frost (October 18).
When should I plant tomatoes in Iowa City?
For Iowa City, sow tomatoes indoors about February 24–March 10 and move the seedlings out around April 28, after the last spring frost.
Never miss a window in Iowa City
An email when it’s time to start seeds, transplant, and sow — timed to Iowa City’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Coralville · 7 km
- North Liberty · 12 km
- Cedar Rapids · 36 km
- Marion · 43 km
- Muscatine · 47 km
- Davenport · 78 km
- Rock Island · 81 km
- Bettendorf · 88 km
Frost dates recorded at IOWA CITY MUNI AP, 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 Iowa City, IA — Frost Dates & Zone 5b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USW00014937. Retrieved from https://blissgarden.com/iowa/iowa-city.