Iowa frost dates: C
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Calamus | Apr 27 | Oct 10 | 166 d | 5b |
| Callender | Apr 28 | Oct 8 | 163 d | 5a |
| Calmar | May 3 | Oct 7 | 157 d | 5a |
| Calumet | Apr 29 | Oct 10 | 164 d | 5a |
| Camanche | Apr 22 | Oct 16 | 177 d | 5b |
| Cambridge | Apr 26 | Oct 12 | 169 d | 5b |
| Cantril | Apr 26 | Oct 13 | 170 d | 6a |
| Carbon | Apr 27 | Oct 12 | 168 d | 5b |
| Carlisle | Apr 18 | Oct 20 | 185 d | 5b |
| Carpenter | May 4 | Oct 4 | 153 d | 5a |
| Carroll | Apr 27 | Oct 10 | 166 d | 5a |
| Carson | Apr 23 | Oct 14 | 174 d | 5b |
| Carter Lake | Apr 18 | Oct 21 | 186 d | 6a |
| Cascade | Apr 28 | Oct 10 | 165 d | 5a |
| Casey | May 2 | Oct 3 | 154 d | 5b |
| Castalia | May 1 | Oct 3 | 155 d | 5a |
| Castana | Apr 25 | Oct 12 | 170 d | 5b |
| Cedar | Apr 23 | Oct 14 | 174 d | 5b |
| Cedar Falls | Apr 27 | Oct 10 | 166 d | 5a |
| Cedar Rapids | Apr 28 | Oct 12 | 167 d | 5a |
| Center Junction | May 1 | Oct 4 | 156 d | 5a |
| Center Point | May 3 | Oct 3 | 153 d | 5a |
| Centerville | Apr 28 | Oct 14 | 169 d | 5b |
| Central City | May 3 | Oct 7 | 157 d | 5a |
| Chapin | Apr 29 | Oct 9 | 163 d | 5a |
| Chariton | May 5 | Oct 5 | 153 d | 5b |
| Charles City | Apr 30 | Oct 6 | 159 d | 5a |
| Charlotte | Apr 25 | Oct 14 | 172 d | 5a |
| Charter Oak | May 3 | Oct 1 | 151 d | 5a |
| Chatsworth | May 1 | Oct 4 | 156 d | 5a |
| Chelsea | Apr 28 | Oct 10 | 165 d | 5a |
| Cherokee | May 4 | Oct 4 | 153 d | 5a |
| Chester | May 8 | Oct 1 | 146 d | 4b |
| Chillicothe | Apr 23 | Oct 14 | 174 d | 5b |
| Churdan | Apr 26 | Oct 9 | 166 d | 5a |
| Cincinnati | Apr 28 | Oct 14 | 169 d | 5b |
| Clare | Apr 28 | Oct 8 | 163 d | 5a |
| Clarence | Apr 27 | Oct 10 | 166 d | 5a |
| Clarinda | Apr 25 | Oct 11 | 169 d | 5b |
| Clarion | Apr 30 | Oct 10 | 163 d | 5a |
| Clarksville | Apr 27 | Oct 8 | 164 d | 5a |
| Clear Lake | May 3 | Oct 1 | 151 d | 5a |
| Clearfield | Apr 25 | Oct 12 | 170 d | 5b |
| Cleghorn | May 4 | Oct 4 | 153 d | 5a |
| Clemons | Apr 24 | Oct 12 | 171 d | 5a |
| Clermont | May 1 | Oct 3 | 155 d | 5a |
| Climbing Hill | Apr 29 | Oct 5 | 159 d | 5a |
| Clinton | Apr 13 | Oct 26 | 196 d | 5b |
| Clio | Apr 21 | Oct 19 | 181 d | 5b |
| Clive | Apr 18 | Oct 20 | 185 d | 5b |
| Clutier | Apr 30 | Oct 9 | 162 d | 5a |
| Coggon | May 3 | Oct 7 | 157 d | 5a |
| Coin | Apr 20 | Oct 17 | 180 d | 5b |
| Colesburg | Apr 21 | Oct 18 | 180 d | 5a |
| Colfax | Apr 21 | Oct 15 | 177 d | 5b |
| College Springs | Apr 25 | Oct 11 | 169 d | 5b |
| Collins | Apr 24 | Oct 12 | 171 d | 5b |
| Colo | Apr 24 | Oct 12 | 171 d | 5a |
| Columbia | Apr 20 | Oct 19 | 182 d | 5b |
| Columbus City | Apr 26 | Oct 10 | 167 d | 5b |
| Columbus Junction | Apr 26 | Oct 10 | 167 d | 5b |
| Colwell | Apr 30 | Oct 6 | 159 d | 5a |
| Conesville | Apr 26 | Oct 10 | 167 d | 5b |
| Conrad | Apr 30 | Oct 6 | 159 d | 5a |
| Conroy | Apr 28 | Oct 9 | 164 d | 5a |
| Coon Rapids | Apr 27 | Oct 10 | 166 d | 5a |
| Cooper | Apr 26 | Oct 9 | 166 d | 5b |
| Coralville | Apr 21 | Oct 18 | 180 d | 5b |
| Corning | Apr 27 | Oct 12 | 168 d | 5b |
| Correctionville | Apr 30 | Oct 9 | 162 d | 5a |
| Corwith | Apr 29 | Oct 7 | 161 d | 5a |
| Corydon | Apr 21 | Oct 19 | 181 d | 5b |
| Coulter | Apr 29 | Oct 9 | 163 d | 5a |
| Council Bluffs | Apr 18 | Oct 21 | 186 d | 6a |
| Crawfordsville | Apr 28 | Oct 11 | 166 d | 5b |
| Crescent | Apr 18 | Oct 21 | 186 d | 5b |
| Cresco | May 8 | Oct 1 | 146 d | 4b |
| Creston | Apr 28 | Oct 11 | 166 d | 5b |
| Cromwell | Apr 28 | Oct 11 | 166 d | 5b |
| Crystal Lake | Apr 29 | Oct 7 | 161 d | 5a |
| Cumberland | Apr 30 | Oct 2 | 155 d | 5b |
| Cumming | Apr 18 | Oct 20 | 185 d | 5b |
| Curlew | Apr 27 | Oct 7 | 163 d | 5a |
| Cushing | Apr 30 | Oct 9 | 162 d | 5a |
| Cylinder | Apr 27 | Oct 7 | 163 d | 5a |