Wisconsin frost dates: F
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Fairchild | May 7 | Oct 1 | 147 d | 4b |
| Fairwater | May 8 | Oct 2 | 147 d | 5a |
| Fall Creek | May 7 | Oct 1 | 147 d | 4b |
| Fall River | May 1 | Oct 11 | 163 d | 5a |
| Fence | May 24 | Sep 30 | 129 d | 4b |
| Fennimore | May 3 | Oct 7 | 157 d | 5a |
| Ferryville | May 3 | Oct 7 | 157 d | 5a |
| Fifield | May 15 | Sep 28 | 136 d | 4a |
| Fish Creek | May 14 | Oct 18 | 157 d | 5b |
| Florence | May 24 | Sep 25 | 124 d | 4b |
| Fond Du Lac | May 1 | Oct 10 | 162 d | 5b |
| Fontana | Apr 28 | Oct 14 | 169 d | 5b |
| Footville | Apr 26 | Oct 15 | 172 d | 5b |
| Forest Junction | May 6 | Oct 6 | 153 d | 5b |
| Forestville | May 6 | Oct 17 | 164 d | 5b |
| Fort Atkinson | Apr 28 | Oct 13 | 168 d | 5b |
| Fountain City | Apr 23 | Oct 21 | 181 d | 4b |
| Fox Lake | May 1 | Oct 11 | 163 d | 5a |
| Foxboro | May 18 | Oct 3 | 138 d | 4a |
| Francis Creek | Apr 27 | Oct 21 | 177 d | 5b |
| Franklin | May 3 | Oct 14 | 164 d | 5b |
| Franksville | May 5 | Oct 8 | 156 d | 5b |
| Frederic | May 6 | Oct 4 | 151 d | 4b |
| Fredonia | May 5 | Oct 12 | 160 d | 5b |
| Freedom | May 4 | Oct 6 | 155 d | 5b |
| Fremont | May 4 | Oct 6 | 155 d | 5a |
| Friendship | May 9 | Oct 3 | 147 d | 4b |
| Friesland | May 8 | Oct 2 | 147 d | 5a |