Illinois frost dates: T
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Table Grove | Apr 17 | Oct 22 | 188 d | 6a |
| Tallula | Apr 13 | Oct 21 | 191 d | 6a |
| Tamaroa | Apr 6 | Oct 22 | 199 d | 6b |
| Tamms | Apr 3 | Nov 5 | 216 d | 7a |
| Tampico | Apr 24 | Oct 14 | 173 d | 5b |
| Taylor Ridge | Apr 24 | Oct 18 | 177 d | 5b |
| Taylor Springs | Apr 13 | Oct 24 | 194 d | 6b |
| Taylorville | Apr 12 | Oct 20 | 191 d | 6a |
| Techny | Apr 26 | Oct 21 | 178 d | 6a |
| Tennessee | Apr 21 | Oct 19 | 181 d | 6a |
| Teutopolis | Apr 13 | Oct 24 | 194 d | 6b |
| Texico | Apr 11 | Oct 22 | 194 d | 6b |
| Thawville | Apr 25 | Oct 20 | 178 d | 6a |
| Thayer | Apr 7 | Oct 29 | 205 d | 6a |
| Thebes | Apr 5 | Oct 25 | 203 d | 7a |
| Thomasboro | Apr 21 | Oct 18 | 180 d | 6a |
| Thompsonville | Apr 4 | Oct 28 | 207 d | 6b |
| Thomson | Apr 13 | Oct 26 | 196 d | 5b |
| Thornton | Apr 23 | Oct 20 | 180 d | 6a |
| Tilden | Apr 12 | Oct 22 | 193 d | 7a |
| Tilton | Apr 21 | Oct 20 | 182 d | 6a |
| Timewell | Apr 18 | Oct 21 | 186 d | 6a |
| Tinley Park | Apr 23 | Oct 20 | 180 d | 6a |
| Tiskilwa | Apr 22 | Oct 17 | 178 d | 5b |
| Toledo | Apr 15 | Oct 24 | 192 d | 6b |
| Tolono | Apr 19 | Oct 17 | 181 d | 6a |
| Toluca | Apr 26 | Oct 17 | 174 d | 5b |
| Tonica | Apr 24 | Oct 18 | 177 d | 5b |
| Topeka | Apr 17 | Oct 19 | 185 d | 6a |
| Toulon | Apr 24 | Oct 17 | 176 d | 5b |
| Tovey | Apr 12 | Oct 20 | 191 d | 6a |
| Towanda | Apr 25 | Oct 16 | 174 d | 6a |
| Tower Hill | Apr 17 | Oct 23 | 189 d | 6b |
| Tremont | Apr 21 | Oct 17 | 179 d | 6a |
| Trenton | Apr 12 | Oct 20 | 191 d | 6b |
| Trilla | Apr 11 | Oct 29 | 201 d | 6b |
| Triumph | Apr 24 | Oct 18 | 177 d | 5b |
| Trivoli | Apr 16 | Oct 23 | 190 d | 5b |
| Troy | Apr 12 | Oct 20 | 191 d | 7a |
| Troy Grove | Apr 24 | Oct 18 | 177 d | 5b |
| Tuscola | Apr 15 | Oct 20 | 188 d | 6a |