When to plant in Altoona, IA
USDA Zone 5bEverything below — frost dates, hardiness zone, and what to plant when in Altoona, Iowa — is derived from the closest NOAA station with complete climate normals.
Heads up: the nearest complete-normals station is about 17 km from Altoona, so your yard's frost dates can differ — a low spot or a paved city center can shift them by a week. In zone 5b, Altoona gardeners can grow many hardy perennials, while the last and first frost still dictate the annual vegetable calendar.
Frost probability
ANKENY · 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 Altoona’s own odds, recorded at ANKENY.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 16 | May 3 | Apr 19 | Sep 21 | Oct 4 | Oct 18 |
| 32°F | May 6 | Apr 23 | Apr 8 | Sep 30 | Oct 15 | Oct 28 |
| 28°F | Apr 27 | Apr 13 | Mar 31 | Oct 11 | Oct 25 | Nov 5 |
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 Altoona, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 19 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.
Altoona planting FAQ
When is the last spring frost in Altoona, IA?
Plan for the last spring frost in Altoona around April 23 (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 Altoona, IA?
Expect Altoona's first fall frost near October 15 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.
What hardiness zone is Altoona in?
Altoona 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 Altoona?
Altoona has about 175 frost-free days — a moderate growing season — between the average last spring frost (April 23) and first fall frost (October 15).
When should I plant tomatoes in Altoona?
For Altoona, 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 Altoona
An email when it’s time to start seeds, transplant, and sow — timed to Altoona’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Pleasant Hill · 6 km
- Ankeny · 13 km
- Des Moines · 14 km
- Johnston · 21 km
- Urbandale · 25 km
- Norwalk · 26 km
- Clive · 27 km
- Grimes · 27 km
Frost dates recorded at ANKENY, 17 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 Altoona, IA — Frost Dates & Zone 5b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00130241. Retrieved from https://blissgarden.com/iowa/altoona.