When to plant in Boise City, ID
USDA Zone 7aHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Boise City, Idaho — all computed from Boise City's nearest NOAA weather station.
In zone 7a, Boise City supports a wide range of perennials year-round; the frost dates above are what set your annual vegetable timing.
The average last spring frost in Boise City is now 6 days earlier than in the 1981–2010 normals. See how frost dates are shifting nationwide →
Frost probability
BOISE AIR TERMINAL · 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 Boise City’s own odds, recorded at BOISE AIR TERMINAL.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 29 | May 8 | Apr 23 | Sep 25 | Oct 8 | Oct 25 |
| 32°F | May 9 | Apr 24 | Apr 4 | Oct 5 | Oct 21 | Nov 5 |
| 28°F | Apr 25 | Apr 2 | Mar 10 | Oct 17 | Oct 31 | Nov 19 |
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 Boise City, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 16 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.
Boise City planting FAQ
When is the last spring frost in Boise City, ID?
Boise City's average last spring frost falls near April 24 — 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 Boise City, ID?
In Boise City, the first 32°F freeze of fall lands around October 21 on average. Time your last harvests and any season-extension cover before it.
What hardiness zone is Boise City in?
Boise City 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 Boise City?
Boise City has about 180 frost-free days — a moderate growing season — between the average last spring frost (April 24) and first fall frost (October 21).
When should I plant tomatoes in Boise City?
For Boise City, sow tomatoes indoors about February 27–March 13 and move the seedlings out around May 1, after the last spring frost.
Never miss a window in Boise City
An email when it’s time to start seeds, transplant, and sow — timed to Boise City’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reachFrost dates recorded at BOISE AIR TERMINAL, 4 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 Boise City, ID — Frost Dates & Zone 7a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USW00024131. Retrieved from https://blissgarden.com/idaho/boise-city.