| City | Population | Last spring frost | First fall frost | Growing season | Zone |
|---|---|---|---|---|---|
| Des Moines | 212,086 | Apr 18 | Oct 20 | 184 days | 5b |
| Cedar Rapids | 137,935 | Apr 27 | Oct 11 | 165 days | 5b |
| Davenport | 100,358 | Apr 19 | Oct 22 | 184 days | 5b |
| Sioux City | 86,356 | Apr 29 | Oct 7 | 161 days | 5a |
| Ankeny | 77,833 | Apr 23 | Oct 15 | 173 days | 5b |
| Iowa City | 76,229 | Apr 21 | Oct 18 | 180 days | 5b |
| West Des Moines | 74,224 | Apr 18 | Oct 20 | 184 days | 5b |
| Ames | 68,220 | Apr 26 | Oct 8 | 164 days | 5b |
| Waterloo | 66,919 | Apr 27 | Oct 10 | 165 days | 5a |
| Council Bluffs | 62,680 | Apr 18 | Oct 21 | 185 days | 5b |
| Dubuque | 59,148 | Apr 19 | Oct 21 | 184 days | 5a |
| Urbandale | 48,570 | Apr 19 | Oct 18 | 179 days | 5b |
| Marion | 42,732 | Apr 28 | Oct 12 | 166 days | 5a |
| Cedar Falls | 41,240 | Apr 27 | Oct 10 | 165 days | 5a |
| Bettendorf | 40,710 | Apr 16 | Oct 25 | 190 days | 5b |
| Waukee | 34,890 | Apr 18 | Oct 20 | 184 days | 5b |
| Marshalltown | 27,536 | Apr 28 | Oct 7 | 162 days | 5a |
| Mason City | 26,853 | Apr 29 | Oct 7 | 161 days | 5a |
| Ottumwa | 25,319 | Apr 23 | Oct 14 | 172 days | 5b |
| Johnston | 25,065 | Apr 19 | Oct 18 | 179 days | 5b |
| Fort Dodge | 24,837 | Apr 28 | Oct 8 | 162 days | 5a |
| Clinton | 24,049 | Apr 22 | Oct 16 | 175 days | 5b |
| Coralville | 23,960 | Apr 21 | Oct 18 | 180 days | 5b |
| Burlington | 23,336 | Apr 15 | Oct 20 | 187 days | 6a |
| Muscatine | 23,164 | Apr 24 | Oct 14 | 172 days | 5b |
| Altoona | 22,796 | Apr 23 | Oct 15 | 173 days | 5b |
| North Liberty | 21,976 | Apr 21 | Oct 18 | 180 days | 5b |
| Clive | 19,861 | Apr 18 | Oct 20 | 184 days | 5b |
| Grimes | 17,405 | Apr 19 | Oct 18 | 179 days | 5b |
| Indianola | 16,829 | Apr 24 | Oct 12 | 168 days | 5b |
| Newton | 15,741 | Apr 22 | Oct 17 | 174 days | 5b |
| Norwalk | 15,004 | Apr 18 | Oct 20 | 184 days | 5b |
| Boone | 12,471 | Apr 28 | Oct 12 | 165 days | 5a |
| Storm Lake | 11,590 | Apr 25 | Oct 13 | 170 days | 5a |
| Oskaloosa | 11,493 | Apr 21 | Oct 16 | 176 days | 5b |
| Pleasant Hill | 11,239 | Apr 18 | Oct 20 | 184 days | 5b |
| Spencer | 11,218 | May 1 | Oct 3 | 154 days | 5a |
| Pella | 10,992 | Apr 20 | Oct 19 | 180 days | 5b |
| Le Mars | 10,760 | Apr 30 | Oct 4 | 157 days | 5a |
| Waverly | 10,561 | Apr 27 | Oct 10 | 165 days | 5a |
| Carroll | 10,085 | Apr 27 | Oct 10 | 166 days | 5a |
| Fort Madison | 9,935 | Apr 12 | Oct 25 | 194 days | 6a |
| Bondurant | 9,647 | Apr 23 | Oct 15 | 173 days | 5b |
| Keokuk | 9,510 | Apr 10 | Oct 27 | 198 days | 6a |
| Grinnell | 9,430 | May 3 | Oct 6 | 155 days | 5b |
| Fairfield | 9,220 | Apr 27 | Oct 12 | 168 days | 5b |
| Sioux Center | 8,864 | Apr 30 | Oct 3 | 154 days | 5a |
| Mount Pleasant | 8,500 | Apr 30 | Oct 10 | 163 days | 5b |
| Denison | 8,214 | Apr 27 | Oct 11 | 166 days | 5a |
| Perry | 8,208 | Apr 25 | Oct 10 | 166 days | 5a |
| Webster City | 7,815 | May 3 | Oct 2 | 150 days | 5a |
| Clear Lake | 7,601 | May 3 | Oct 1 | 150 days | 5a |
| Knoxville | 7,469 | Apr 20 | Oct 19 | 180 days | 5b |
| Hiawatha | 7,432 | Apr 28 | Oct 12 | 166 days | 5a |
| Decorah | 7,417 | May 3 | Oct 7 | 157 days | 5a |
| Creston | 7,335 | Apr 28 | Oct 11 | 164 days | 5b |
| Washington | 7,261 | Apr 28 | Oct 11 | 165 days | 5b |
| Tiffin | 7,156 | Apr 21 | Oct 18 | 180 days | 5b |
| Adel | 7,098 | Apr 25 | Oct 10 | 166 days | 5b |
| Charles City | 7,013 | Apr 30 | Oct 6 | 157 days | 5a |
| Nevada | 6,974 | Apr 26 | Oct 12 | 168 days | 5b |
| Eldridge | 6,954 | Apr 21 | Oct 17 | 176 days | 5b |
| Atlantic | 6,676 | Apr 30 | Oct 2 | 153 days | 5a |
| Polk City | 6,630 | Apr 19 | Oct 18 | 179 days | 5b |
| Orange City | 6,468 | Apr 30 | Oct 3 | 154 days | 5a |
| Independence | 6,312 | Apr 30 | Oct 7 | 159 days | 5a |
| Asbury | 6,035 | Apr 19 | Oct 21 | 184 days | 5a |
| Maquoketa | 6,027 | Apr 25 | Oct 14 | 171 days | 5a |
| Anamosa | 5,901 | May 1 | Oct 4 | 154 days | 5a |
| Estherville | 5,807 | May 2 | Oct 3 | 153 days | 5a |
| Oelwein | 5,757 | Apr 30 | Oct 9 | 163 days | 5a |
| DeWitt | 5,704 | Apr 22 | Oct 16 | 175 days | 5b |
| Osceola | 5,679 | Apr 29 | Oct 9 | 162 days | 5b |
| Sheldon | 5,575 | May 5 | Sep 28 | 145 days | 5a |
| Spirit Lake | 5,525 | Apr 28 | Oct 11 | 164 days | 5a |
| Winterset | 5,520 | Apr 30 | Oct 3 | 157 days | 5b |
| Red Oak | 5,388 | Apr 24 | Oct 13 | 169 days | 5b |
| Manchester | 5,357 | May 3 | Oct 4 | 154 days | 5a |
| Centerville | 5,327 | Apr 28 | Oct 14 | 168 days | 5b |
| Sergeant Bluff | 5,324 | Apr 29 | Oct 7 | 161 days | 5a |
| Algona | 5,309 | Apr 30 | Oct 6 | 160 days | 5a |
| Glenwood | 5,287 | Apr 23 | Oct 11 | 170 days | 6a |
| Clarinda | 5,273 | Apr 25 | Oct 11 | 168 days | 5b |
| Cherokee | 5,122 | May 4 | Oct 4 | 152 days | 5a |
| Windsor Heights | 5,059 | Apr 18 | Oct 20 | 184 days | 5b |
| Iowa Falls | 5,013 | Apr 28 | Oct 10 | 164 days | 5a |
| Vinton | 5,004 | May 3 | Oct 3 | 151 days | 5a |