Iowa frost dates: N
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Nashua | Apr 30 | Oct 6 | 159 d | 5a |
| Nemaha | Apr 30 | Oct 6 | 159 d | 5a |
| Neola | Apr 29 | Oct 8 | 162 d | 5b |
| Nevada | Apr 24 | Oct 12 | 171 d | 5b |
| New Albin | Apr 22 | Oct 17 | 178 d | 5a |
| New Hampton | May 2 | Oct 5 | 156 d | 5a |
| New Hartford | Apr 27 | Oct 10 | 166 d | 5a |
| New Liberty | Apr 27 | Oct 10 | 166 d | 5b |
| New London | Apr 30 | Oct 10 | 163 d | 5b |
| New Market | Apr 25 | Oct 11 | 169 d | 5b |
| New Providence | Apr 27 | Oct 10 | 166 d | 5a |
| New Sharon | Apr 21 | Oct 16 | 178 d | 5b |
| New Vienna | Apr 21 | Oct 18 | 180 d | 5a |
| New Virginia | Apr 29 | Oct 9 | 163 d | 5b |
| Newell | Apr 25 | Oct 13 | 171 d | 5a |
| Newhall | May 3 | Oct 3 | 153 d | 5a |
| Newton | Apr 22 | Oct 17 | 178 d | 5b |
| Nichols | Apr 24 | Oct 14 | 173 d | 5b |
| Nodaway | Apr 27 | Oct 12 | 168 d | 5b |
| Nora Springs | Apr 29 | Oct 7 | 161 d | 5a |
| North Buena Vista | Apr 21 | Oct 18 | 180 d | 5a |
| North English | Apr 28 | Oct 9 | 164 d | 5b |
| North Liberty | Apr 21 | Oct 18 | 180 d | 5b |
| North Washington | May 2 | Oct 5 | 156 d | 5a |
| Northboro | Apr 20 | Oct 17 | 180 d | 5b |
| Northwood | May 4 | Oct 4 | 153 d | 5a |
| Norwalk | Apr 18 | Oct 20 | 185 d | 5b |
| Norway | Apr 27 | Oct 11 | 167 d | 5a |