Colorado frost dates: S
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Saguache | May 16 | Sep 28 | 135 d | 5b |
| Salida | May 29 | Sep 20 | 114 d | 5b |
| San Luis | May 31 | Sep 23 | 115 d | 5b |
| Sanford | May 28 | Sep 21 | 116 d | 5a |
| Sargents | frost any month | 5b | ||
| Sedalia | May 16 | Oct 1 | 138 d | 5b |
| Sedgwick | May 6 | Oct 7 | 154 d | 5b |
| Seibert | May 4 | Oct 11 | 160 d | 5b |
| Severance | May 3 | Oct 6 | 156 d | 5b |
| Shawnee | Jun 16 | Sep 8 | 84 d | 5b |
| Sheridan Lake | Apr 27 | Oct 15 | 171 d | 6a |
| Silt | May 11 | Oct 4 | 146 d | 6a |
| Silver Plume | May 30 | Sep 19 | 112 d | 5a |
| Silverthorne | frost any month | 4b | ||
| Silverton | frost any month | 5a | ||
| Simla | May 12 | Oct 2 | 143 d | 5b |
| Slater | Jun 1 | Sep 18 | 109 d | 5b |
| Snowmass | May 31 | Sep 23 | 115 d | 6a |
| Snowmass Village | May 31 | Sep 23 | 115 d | 5b |
| Snyder | May 6 | Oct 6 | 153 d | 5b |
| Somerset | May 3 | Oct 12 | 162 d | 6a |
| South Fork | May 23 | Sep 25 | 125 d | 5b |
| Springfield | May 3 | Oct 10 | 160 d | 6b |
| Steamboat Springs | Jun 9 | Sep 12 | 95 d | 4b |
| Sterling | Apr 30 | Oct 9 | 162 d | 5b |
| Stoneham | May 9 | Oct 4 | 148 d | 5b |
| Strasburg | May 13 | Oct 2 | 142 d | 5b |
| Stratton | May 6 | Oct 9 | 156 d | 6a |
| Sugar City | May 2 | Oct 8 | 159 d | 5b |
| Swink | May 1 | Oct 8 | 160 d | 6a |