North Dakota frost dates: S
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Saint Anthony | May 14 | Sep 27 | 136 d | 4a |
| Saint John | May 19 | Sep 24 | 128 d | 3b |
| Saint Michael | May 6 | Oct 5 | 152 d | 4a |
| Saint Thomas | May 4 | Oct 7 | 156 d | 4a |
| Sanborn | May 13 | Sep 26 | 136 d | 4a |
| Sarles | May 18 | Sep 23 | 128 d | 3b |
| Sawyer | May 22 | Sep 22 | 123 d | 4a |
| Scranton | May 16 | Sep 25 | 132 d | 4b |
| Selfridge | May 9 | Sep 30 | 144 d | 4b |
| Sentinel Butte | May 16 | Sep 26 | 133 d | 4a |
| Sharon | May 17 | Sep 23 | 129 d | 4a |
| Sheldon | May 3 | Oct 5 | 155 d | 4a |
| Sherwood | May 17 | Sep 23 | 129 d | 3b |
| Sheyenne | May 12 | Sep 29 | 140 d | 4a |
| Shields | May 13 | Sep 27 | 137 d | 4a |
| Solen | May 12 | Sep 24 | 135 d | 4a |
| Souris | May 14 | Sep 25 | 134 d | 3b |
| South Heart | May 18 | Sep 25 | 130 d | 4b |
| Spiritwood | May 11 | Sep 28 | 140 d | 4a |
| Stanley | May 17 | Sep 23 | 129 d | 4a |
| Stanton | May 12 | Oct 3 | 144 d | 4a |
| Starkweather | May 15 | Sep 22 | 130 d | 4a |
| Steele | May 15 | Sep 25 | 133 d | 4a |
| Sterling | May 11 | Sep 29 | 141 d | 4a |
| Stirum | May 8 | Sep 28 | 143 d | 4a |
| Strasburg | May 12 | Sep 29 | 140 d | 4a |
| Streeter | May 13 | Sep 30 | 140 d | 4a |
| Surrey | May 10 | Oct 1 | 144 d | 4a |
| Sutton | May 12 | Sep 28 | 139 d | 4a |
| Sykeston | May 10 | Sep 28 | 141 d | 4a |