When to Plant Tomatoes in Wyoming
In Wyoming, the time to transplant tomatoes outside runs from May 17 – May 31 in Casper to Jun 27 – Jul 11 in Jackson. In Cheyenne, it's May 21 – Jun 4. The average last spring frost differs by about 6 weeks across the state (May 10 in Casper, Jun 20 in Jackson), so use the dates for the town nearest you.
Tomatoes are killed by frost and sulk in cold soil. Wait until nights stay above 50°F, usually one to three weeks after the average last frost.
- Start indoors: 6–8 weeks before the last frost.
- Transplant outside: 1–3 weeks after the last frost.
Tomatoes planting dates in Wyoming by city
| City | Zone | Start indoors | Transplant outside |
|---|---|---|---|
| Casper | 5a | Mar 15 – Mar 29 | May 17 – May 31 |
| Cheyenne | 5b | Mar 19 – Apr 2 | May 21 – Jun 4 |
| Cody | 5a | Mar 17 – Mar 31 | May 19 – Jun 2 |
| Douglas | 5a | Mar 24 – Apr 7 | May 26 – Jun 9 |
| Evanston | 5a | Apr 17 – May 1 | Jun 19 – Jul 3 |
| Gillette | 4b | Mar 20 – Apr 3 | May 22 – Jun 5 |
| Green River | 5a | Mar 29 – Apr 12 | May 31 – Jun 14 |
| Jackson | 4b | Apr 25 – May 9 | Jun 27 – Jul 11 |
| Lander | 5a | Mar 23 – Apr 6 | May 25 – Jun 8 |
| Laramie | 4a | Apr 12 – Apr 26 | Jun 14 – Jun 28 |
| Powell | 5a | Mar 24 – Apr 7 | May 26 – Jun 9 |
| Rawlins | 5a | Mar 22 – Apr 5 | May 24 – Jun 7 |
| Riverton | 5a | Mar 17 – Mar 31 | May 19 – Jun 2 |
| Rock Springs | 5a | Mar 29 – Apr 12 | May 31 – Jun 14 |
| Sheridan | 5a | Mar 26 – Apr 9 | May 28 – Jun 11 |
| Torrington | 5a | Mar 16 – Mar 30 | May 18 – Jun 1 |
Calculated from each town's average (50%) frost dates, from the nearest NOAA station (1991–2020). Typical dates for the 2027 planting season, based on NOAA's 1991–2020 averages. They are long-term odds, not a forecast: always check your local forecast before planting. Zones: 2023 USDA Plant Hardiness Zone Map (USDA-ARS and Oregon State University). Not the official map; see planthardiness.ars.usda.gov.
See all frost dates in Wyoming, or the general guide to when to plant tomatoes.
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