Illinois frost dates: K
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Kampsville | Apr 20 | Oct 20 | 183 d | 6a |
| Kane | Apr 14 | Oct 19 | 188 d | 6b |
| Kaneville | Apr 28 | Oct 13 | 168 d | 5b |
| Kankakee | Apr 19 | Oct 24 | 188 d | 5b |
| Kansas | Apr 15 | Oct 23 | 191 d | 6a |
| Karbers Ridge | Apr 19 | Oct 20 | 184 d | 7a |
| Karnak | Apr 3 | Nov 5 | 216 d | 7a |
| Kasbeer | Apr 24 | Oct 14 | 173 d | 5b |
| Keenes | Apr 11 | Oct 22 | 194 d | 6b |
| Keensburg | Apr 2 | Oct 31 | 212 d | 6b |
| Keithsburg | Apr 14 | Oct 24 | 193 d | 5b |
| Kell | Apr 9 | Oct 24 | 198 d | 6b |
| Kempton | Apr 25 | Oct 20 | 178 d | 5b |
| Kenilworth | Apr 26 | Oct 21 | 178 d | 6a |
| Kenney | Apr 20 | Oct 16 | 179 d | 6a |
| Kent | Apr 27 | Oct 9 | 165 d | 5a |
| Kewanee | Apr 24 | Oct 17 | 176 d | 5b |
| Keyesport | Apr 6 | Oct 29 | 206 d | 6b |
| Kilbourne | Apr 17 | Oct 19 | 185 d | 6a |
| Kincaid | Apr 12 | Oct 20 | 191 d | 6a |
| Kinderhook | Apr 4 | Nov 4 | 214 d | 6a |
| Kingston | Apr 24 | Oct 18 | 177 d | 5b |
| Kingston Mines | Apr 16 | Oct 23 | 190 d | 6a |
| Kinmundy | Apr 9 | Oct 26 | 200 d | 6b |
| Kinsman | Apr 27 | Oct 15 | 171 d | 5b |
| Kirkland | Apr 24 | Oct 18 | 177 d | 5b |
| Kirkwood | Apr 22 | Oct 14 | 175 d | 5b |
| Knoxville | Apr 21 | Oct 20 | 182 d | 5b |