When to plant in Rock Springs, WY
USDA Zone 5aEverything below — frost dates, hardiness zone, and what to plant when in Rock Springs, Wyoming — is derived from the closest NOAA station with complete climate normals.
In zone 5a, Rock Springs gardeners can grow many hardy perennials, while the last and first frost still dictate the annual vegetable calendar.
Frost probability
ROCK SPRINGS FIRE DEPT · 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 Rock Springs’s own odds, recorded at ROCK SPRINGS FIRE DEPT.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Jun 21 | Jun 6 | May 24 | Sep 2 | Sep 14 | Sep 25 |
| 32°F | Jun 9 | May 24 | May 8 | Sep 9 | Sep 24 | Oct 4 |
| 28°F | May 26 | May 9 | Apr 25 | Sep 19 | Oct 3 | Oct 17 |
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 Rock Springs, 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.
Rock Springs planting FAQ
When is the last spring frost in Rock Springs, WY?
Rock Springs's average last spring frost falls near May 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 Rock Springs, WY?
Expect Rock Springs's first fall frost near September 24 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.
What hardiness zone is Rock Springs in?
Rock Springs is in USDA hardiness zone 5a. In zone 5a, winters are cold — pick cold-hardy varieties and protect tender crops.
How long is the growing season in Rock Springs?
Rock Springs has about 123 frost-free days — a short growing season — between the average last spring frost (May 24) and first fall frost (September 24).
When should I plant tomatoes in Rock Springs?
For Rock Springs, sow tomatoes indoors about March 29–April 12 and move the seedlings out around May 31, after the last spring frost.
Never miss a window in Rock Springs
An email when it’s time to start seeds, transplant, and sow — timed to Rock Springs’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Green River · 23 km
- Vernal · 130 km
- Evanston · 150 km
- Riverton · 174 km
- North Logan · 216 km
- Heber · 216 km
- Smithfield · 218 km
- Hyrum · 218 km
Frost dates recorded at ROCK SPRINGS FIRE DEPT, 2 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 Rock Springs, WY — Frost Dates & Zone 5a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00487847. Retrieved from https://blissgarden.com/wyoming/rock-springs.