When to plant in Caldwell, ID
USDA Zone 7aCaldwell, Idaho frost dates, USDA zone, and a full-year planting calendar, drawn from the nearest NOAA station and tuned to the local season.
Zone 7a means many perennials and even some tender shrubs overwinter in Caldwell, while your frost dates still decide when annuals go out.
The average first fall frost in Caldwell is now 5 days later than in the 1981–2010 normals. See how frost dates are shifting nationwide →
Frost probability
NAMPA SUGAR FACTORY · 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 Caldwell’s own odds, recorded at NAMPA SUGAR FACTORY.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Jun 6 | May 16 | May 1 | Sep 15 | Sep 30 | Oct 14 |
| 32°F | May 18 | Apr 29 | Apr 15 | Sep 29 | Oct 13 | Oct 28 |
| 28°F | May 1 | Apr 11 | Mar 25 | Oct 9 | Oct 25 | Nov 10 |
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 Caldwell, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 22 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.
Caldwell planting FAQ
When is the last spring frost in Caldwell, ID?
Plan for the last spring frost in Caldwell around April 29 (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 Caldwell, ID?
In Caldwell, the first 32°F freeze of fall lands around October 13 on average. Time your last harvests and any season-extension cover before it.
What hardiness zone is Caldwell in?
Caldwell is in USDA hardiness zone 7a. In zone 7a, winters are moderate — most common vegetables grow well in season.
How long is the growing season in Caldwell?
There are roughly 167 frost-free days in Caldwell (a moderate growing season), running from the average last frost around April 29 to the first fall frost near October 13.
When should I plant tomatoes in Caldwell?
In Caldwell, start tomato seeds indoors around March 4–March 18, then transplant seedlings outdoors around May 6 once the danger of frost has passed.
Never miss a window in Caldwell
An email when it’s time to start seeds, transplant, and sow — timed to Caldwell’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Middleton · 8 km
- Nampa · 10 km
- Star · 15 km
- Eagle · 21 km
- Meridian · 21 km
- Kuna · 25 km
- Garden City · 29 km
- Boise City · 35 km
Frost dates recorded at NAMPA SUGAR FACTORY, 8 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 Caldwell, ID — Frost Dates & Zone 7a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00106305. Retrieved from https://blissgarden.com/idaho/caldwell.