South Dakota frost dates: N
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Nemo | May 20 | Sep 25 | 128 d | 5a |
| New Effington | May 4 | Oct 3 | 152 d | 4b |
| New Holland | May 3 | Oct 6 | 156 d | 5a |
| New Underwood | May 12 | Oct 1 | 142 d | 5a |
| Newell | May 8 | Oct 1 | 146 d | 4b |
| Nisland | May 8 | Oct 1 | 146 d | 4b |
| Norris | May 6 | Oct 4 | 151 d | 5a |
| North Sioux City | Apr 29 | Oct 7 | 161 d | 5a |
| Northville | May 11 | Sep 27 | 139 d | 4a |
| Nunda | May 2 | Oct 5 | 156 d | 4b |