Illinois frost dates: C
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Cabery | Apr 27 | Oct 15 | 171 d | 5b |
| Cairo | Apr 2 | Oct 31 | 212 d | 7a |
| Caledonia | May 1 | Oct 12 | 164 d | 5b |
| Calhoun | Apr 15 | Oct 23 | 191 d | 6b |
| Calumet City | Apr 23 | Oct 20 | 180 d | 6a |
| Camargo | Apr 15 | Oct 20 | 188 d | 6a |
| Cambria | Apr 9 | Oct 22 | 196 d | 7a |
| Cambridge | Apr 20 | Oct 20 | 183 d | 5b |
| Camden | Apr 16 | Oct 23 | 190 d | 6a |
| Cameron | Apr 20 | Oct 19 | 182 d | 5b |
| Camp Grove | Apr 20 | Oct 17 | 180 d | 5b |
| Camp Point | Apr 18 | Oct 21 | 186 d | 6a |
| Campbell Hill | Apr 12 | Oct 22 | 193 d | 7a |
| Campus | Apr 27 | Oct 15 | 171 d | 5b |
| Canton | Apr 17 | Oct 19 | 185 d | 6a |
| Cantrall | Apr 14 | Oct 20 | 189 d | 6a |
| Capron | Apr 30 | Oct 10 | 163 d | 5b |
| Carbon Cliff | Apr 16 | Oct 25 | 192 d | 5b |
| Carbondale | Apr 9 | Oct 22 | 196 d | 7a |
| Carlinville | Apr 14 | Oct 21 | 190 d | 6b |
| Carlock | Apr 21 | Oct 17 | 179 d | 5b |
| Carlyle | Apr 6 | Oct 29 | 206 d | 6b |
| Carman | Apr 18 | Oct 20 | 185 d | 6a |
| Carmi | Apr 15 | Oct 19 | 187 d | 7a |
| Carol Stream | Apr 28 | Oct 16 | 171 d | 5b |
| Carpentersville | Apr 26 | Oct 18 | 175 d | 5b |
| Carrier Mills | Apr 7 | Oct 26 | 202 d | 7a |
| Carrollton | Apr 13 | Oct 22 | 192 d | 6a |
| Carterville | Apr 9 | Oct 22 | 196 d | 7a |
| Carthage | Apr 13 | Oct 22 | 192 d | 6a |
| Cary | May 1 | Oct 11 | 163 d | 5b |
| Casey | Apr 14 | Oct 20 | 189 d | 6b |
| Caseyville | Apr 8 | Oct 26 | 201 d | 7a |
| Castleton | Apr 24 | Oct 17 | 176 d | 5b |
| Catlin | Apr 21 | Oct 20 | 182 d | 6a |
| Cave In Rock | Apr 19 | Oct 20 | 184 d | 7a |
| Cedar Point | Apr 24 | Oct 18 | 177 d | 5b |
| Cedarville | Apr 26 | Oct 13 | 170 d | 5a |
| Centralia | Apr 9 | Oct 24 | 198 d | 6b |
| Cerro Gordo | Apr 16 | Oct 22 | 189 d | 6a |
| Chadwick | May 2 | Oct 7 | 158 d | 5a |
| Chambersburg | Apr 18 | Oct 15 | 180 d | 6a |
| Champaign | Apr 15 | Oct 24 | 192 d | 6a |
| Chana | Apr 26 | Oct 13 | 170 d | 5b |
| Chandlerville | Apr 13 | Oct 21 | 191 d | 6a |
| Channahon | Apr 16 | Oct 26 | 193 d | 5b |
| Chapin | Apr 18 | Oct 20 | 185 d | 6a |
| Charleston | Apr 15 | Oct 23 | 191 d | 6a |
| Chatham | Apr 15 | Oct 22 | 190 d | 6a |
| Chatsworth | Apr 25 | Oct 20 | 178 d | 6a |
| Chebanse | Apr 19 | Oct 24 | 188 d | 5b |
| Chenoa | Apr 23 | Oct 15 | 175 d | 5b |
| Cherry | Apr 24 | Oct 18 | 177 d | 5b |
| Cherry Valley | Apr 24 | Oct 17 | 176 d | 5b |
| Chester | Apr 8 | Oct 30 | 205 d | 7a |
| Chesterfield | Apr 14 | Oct 21 | 190 d | 6b |
| Chestnut | Apr 20 | Oct 16 | 179 d | 6a |
| Chicago | Apr 10 | Nov 5 | 209 d | 6b |
| Chicago Heights | Apr 23 | Oct 20 | 180 d | 6a |
| Chicago Ridge | Apr 10 | Nov 1 | 205 d | 6a |
| Chillicothe | Apr 20 | Oct 17 | 180 d | 6a |
| Chrisman | Apr 21 | Oct 20 | 182 d | 6a |
| Christopher | Apr 4 | Oct 27 | 206 d | 7a |
| Cicero | Apr 11 | Oct 31 | 203 d | 6a |
| Cisco | Apr 16 | Oct 22 | 189 d | 6a |
| Cisne | Apr 7 | Oct 26 | 202 d | 6b |
| Cissna Park | Apr 22 | Oct 19 | 180 d | 6a |
| Clare | Apr 24 | Oct 18 | 177 d | 5b |
| Claremont | Apr 15 | Oct 23 | 191 d | 6b |
| Clarendon Hills | Apr 28 | Oct 16 | 171 d | 6a |
| Clay City | Apr 9 | Oct 24 | 198 d | 6b |
| Clayton | Apr 18 | Oct 21 | 186 d | 6a |
| Claytonville | Apr 22 | Oct 19 | 180 d | 6a |
| Clifton | Apr 24 | Oct 16 | 175 d | 5b |
| Clinton | Apr 20 | Oct 16 | 179 d | 6a |
| Coal City | Apr 16 | Oct 26 | 193 d | 5b |
| Coal Valley | Apr 24 | Oct 18 | 177 d | 5b |
| Coatsburg | Apr 14 | Oct 23 | 192 d | 6a |
| Cobden | Apr 8 | Oct 29 | 204 d | 7a |
| Coello | Apr 4 | Oct 27 | 206 d | 7a |
| Coffeen | Apr 13 | Oct 24 | 194 d | 6b |
| Colchester | Apr 21 | Oct 19 | 181 d | 6a |
| Colfax | Apr 23 | Oct 15 | 175 d | 6a |
| Collinsville | Apr 8 | Oct 26 | 201 d | 7a |
| Collison | Apr 21 | Oct 20 | 182 d | 6a |
| Colona | Apr 16 | Oct 25 | 192 d | 5b |
| Colp | Apr 9 | Oct 22 | 196 d | 7a |
| Columbia | Apr 6 | Oct 27 | 204 d | 7a |
| Colusa | Apr 12 | Oct 25 | 196 d | 6a |
| Compton | Apr 27 | Oct 12 | 168 d | 5b |
| Concord | Apr 17 | Oct 21 | 187 d | 6a |
| Congerville | Apr 21 | Oct 17 | 179 d | 5b |
| Cooksville | Apr 25 | Oct 16 | 174 d | 6a |
| Cordova | Apr 22 | Oct 16 | 177 d | 5b |
| Cornell | Apr 12 | Oct 28 | 199 d | 5b |
| Cornland | Apr 20 | Oct 16 | 179 d | 6a |
| Cortland | Apr 24 | Oct 18 | 177 d | 5b |
| Cottage Hills | Apr 4 | Nov 5 | 215 d | 7a |
| Coulterville | Apr 12 | Oct 22 | 193 d | 6b |
| Country Club Hills | Apr 23 | Oct 20 | 180 d | 6a |
| Cowden | Apr 15 | Oct 19 | 187 d | 6b |
| Creal Springs | Apr 14 | Oct 21 | 190 d | 7a |
| Crescent City | Apr 24 | Oct 16 | 175 d | 5b |
| Crest Hill | Apr 20 | Oct 22 | 185 d | 6a |
| Creston | Apr 26 | Oct 13 | 170 d | 5b |
| Crestwood | Apr 10 | Nov 1 | 205 d | 6a |
| Crete | Apr 23 | Oct 20 | 180 d | 6a |
| Creve Coeur | Apr 16 | Oct 23 | 190 d | 6a |
| Cropsey | Apr 21 | Oct 17 | 179 d | 6a |
| Crossville | Apr 7 | Oct 25 | 201 d | 7a |
| Crystal Lake | Apr 25 | Oct 22 | 180 d | 5b |
| Cuba | Apr 17 | Oct 19 | 185 d | 6a |
| Cullom | Apr 25 | Oct 20 | 178 d | 5b |
| Cutler | Apr 12 | Oct 22 | 193 d | 7a |
| Cypress | Apr 3 | Nov 5 | 216 d | 7a |