When to plant in Gillette, WY
USDA Zone 4bGillette, Wyoming frost dates, USDA zone, and a full-year planting calendar, drawn from the nearest NOAA station and tuned to the local season.
Zone 4b is cold — in Gillette, most perennials must be fully hardy, and your frost dates set a tight window for tender annual vegetables.
The average first fall frost in Gillette is now 5 days later than in the 1981–2010 normals. See how frost dates are shifting nationwide →
Frost probability
GILLETTE 4SE · 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 Gillette’s own odds, recorded at GILLETTE 4SE.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Jun 12 | May 28 | May 14 | Sep 6 | Sep 21 | Oct 3 |
| 32°F | May 27 | May 15 | May 1 | Sep 15 | Oct 1 | Oct 14 |
| 28°F | May 15 | May 2 | Apr 18 | Sep 26 | Oct 10 | Oct 23 |
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 Gillette, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 36 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.
Gillette planting FAQ
When is the last spring frost in Gillette, WY?
Plan for the last spring frost in Gillette around May 15 (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 Gillette, WY?
In Gillette, the first 32°F freeze of fall lands around October 1 on average. Time your last harvests and any season-extension cover before it.
What hardiness zone is Gillette in?
Gillette is in USDA hardiness zone 4b. In zone 4b, winters are cold — pick cold-hardy varieties and protect tender crops.
How long is the growing season in Gillette?
There are roughly 139 frost-free days in Gillette (a short growing season), running from the average last frost around May 15 to the first fall frost near October 1.
When should I plant tomatoes in Gillette?
In Gillette, start tomato seeds indoors around March 20–April 3, then transplant seedlings outdoors around May 22 once the danger of frost has passed.
Never miss a window in Gillette
An email when it’s time to start seeds, transplant, and sow — timed to Gillette’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reachFrost dates recorded at GILLETTE 4SE, 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 Gillette, WY — Frost Dates & Zone 4b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00483855. Retrieved from https://blissgarden.com/wyoming/gillette.