Frost Dates & Planting Calendars in Wyoming
Typical last spring frost, first fall frost, and growing-season length for 20 cities in Wyoming, based on NOAA 1991–2020 climate normals. Click a city for its full frost-date summary, monthly temperature chart, and 42-crop planting calendar.
| City | Last Spring Frost (typical) | First Fall Frost (typical) | Growing Season | USDA Zone |
|---|---|---|---|---|
| Cheyenne | May 14 | October 1 | 139 days | 5b |
| Casper | May 10 | September 29 | 138 days | 5a |
| Gillette | May 15 | October 1 | 136 days | 5a |
| Laramie | June 7 | September 4 | 88 days | 5b |
| Rock Springs | May 24 | September 24 | 121 days | 5b |
| Sheridan | May 21 | September 23 | 123 days | 5a |
| Green River | May 24 | September 22 | 120 days | 5a |
| Evanston | June 12 | September 12 | 90 days | 5a |
| Riverton | May 12 | September 24 | 132 days | 5a |
| Jackson | Frost-free | Frost-free | Year-round | 4b |
| Cody | May 12 | October 1 | 140 days | 5a |
| Rawlins | May 17 | October 2 | 138 days | 5a |
| Lander | May 18 | September 27 | 131 days | 5a |
| Torrington | May 11 | September 29 | 139 days | 5a |
| Douglas | May 19 | September 23 | 126 days | 5a |
| Powell | May 19 | September 20 | 123 days | 5a |
| Ranchettes | May 12 | October 1 | 141 days | 5b |
| Worland | May 4 | October 1 | 149 days | 4b |
| Buffalo | May 24 | September 21 | 118 days | 5a |
| South Greeley | May 14 | October 1 | 139 days | 5b |