| City | Population | Last spring frost | First fall frost | Growing season | Zone |
|---|---|---|---|---|---|
| Cheyenne | 66,507 | May 14 | Oct 1 | 139 days | 5b |
| Casper | 58,771 | May 10 | Sep 29 | 138 days | 5a |
| Gillette | 34,024 | May 15 | Oct 1 | 136 days | 4b |
| Laramie | 32,284 | Jun 7 | Sep 4 | 88 days | 4a |
| Rock Springs | 22,936 | May 24 | Sep 24 | 121 days | 5a |
| Sheridan | 20,015 | May 21 | Sep 23 | 123 days | 5a |
| Evanston | 11,705 | Jun 12 | Sep 12 | 90 days | 5a |
| Green River | 11,450 | May 24 | Sep 22 | 120 days | 5a |
| Riverton | 10,910 | May 12 | Sep 24 | 132 days | 5a |
| Jackson | 10,720 | Jun 20 | Aug 31 | 70 days | 4b |
| Cody | 10,377 | May 12 | Oct 1 | 140 days | 5a |
| Rawlins | 7,745 | May 17 | Oct 2 | 138 days | 5a |
| Lander | 7,379 | May 18 | Sep 27 | 131 days | 5a |
| Powell | 6,574 | May 19 | Sep 20 | 123 days | 5a |
| Douglas | 6,469 | May 19 | Sep 23 | 126 days | 5a |
| Torrington | 6,205 | May 11 | Sep 29 | 139 days | 5a |