When to plant in Lewiston, ID
USDA Zone 7aEverything below — frost dates, hardiness zone, and what to plant when in Lewiston, Idaho — is derived from the closest NOAA station with complete climate normals.
In zone 7a, Lewiston 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 Lewiston is now 6 days earlier than in the 1981–2010 normals. See how frost dates are shifting nationwide →
Frost probability
LEWISTON NEZ PERCE CO 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 Lewiston’s own odds, recorded at LEWISTON NEZ PERCE CO AP.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 12 | Apr 29 | Apr 11 | Oct 1 | Oct 13 | Oct 28 |
| 32°F | Apr 26 | Apr 6 | Mar 20 | Oct 10 | Oct 26 | Nov 12 |
| 28°F | Apr 4 | Mar 15 | Feb 25 | Oct 20 | Nov 8 | Nov 28 |
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 Lewiston, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 40 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.
Lewiston planting FAQ
When is the last spring frost in Lewiston, ID?
Plan for the last spring frost in Lewiston around April 6 (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 Lewiston, ID?
In Lewiston, the first 32°F freeze of fall lands around October 26 on average. Time your last harvests and any season-extension cover before it.
What hardiness zone is Lewiston in?
Lewiston 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 Lewiston?
Lewiston has about 203 frost-free days — a moderate growing season — between the average last spring frost (April 6) and first fall frost (October 26).
When should I plant tomatoes in Lewiston?
For Lewiston, sow tomatoes indoors about February 9–February 23 and move the seedlings out around April 13, after the last spring frost.
Never miss a window in Lewiston
An email when it’s time to start seeds, transplant, and sow — timed to Lewiston’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Moscow · 38 km
- Pullman · 40 km
- Walla Walla · 110 km
- Cheney · 130 km
- Liberty Lake · 142 km
- Spokane Valley · 142 km
- Spokane · 146 km
- La Grande · 146 km
Frost dates recorded at LEWISTON NEZ PERCE CO 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 Lewiston, ID — Frost Dates & Zone 7a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USW00024149. Retrieved from https://blissgarden.com/idaho/lewiston.