North Dakota frost dates: F
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Fairdale | May 15 | Sep 22 | 130 d | 3b |
| Fairfield | May 12 | Sep 28 | 139 d | 4a |
| Fairmount | May 4 | Oct 3 | 152 d | 4a |
| Fargo | May 4 | Oct 2 | 151 d | 4a |
| Fessenden | May 13 | Sep 28 | 138 d | 4a |
| Fingal | May 3 | Oct 5 | 155 d | 4a |
| Finley | May 17 | Sep 23 | 129 d | 4a |
| Flasher | May 13 | Sep 27 | 137 d | 4a |
| Flaxton | May 20 | Sep 19 | 122 d | 3b |
| Forbes | May 4 | Oct 2 | 151 d | 4b |
| Fordville | May 11 | Sep 28 | 140 d | 4a |
| Forest River | May 4 | Oct 7 | 156 d | 4a |
| Forman | May 7 | Oct 1 | 147 d | 4a |
| Fort Ransom | May 12 | Sep 27 | 138 d | 4a |
| Fort Totten | May 12 | Sep 30 | 141 d | 4a |
| Fort Yates | May 12 | Sep 28 | 139 d | 4a |
| Fortuna | May 19 | Sep 17 | 121 d | 3b |
| Fredonia | May 6 | Oct 4 | 151 d | 4b |
| Fullerton | May 9 | Sep 28 | 142 d | 4b |