USDA hardiness zones in Iowa
| Zone | Avg. extreme minimum | ZIP codes | Example cities |
|---|---|---|---|
| Zone 4b | −25 to −20°F | 16 | — |
| Zone 5a | −20 to −15°F | 534 | Sioux City, Waterloo, Dubuque, Marion |
| Zone 5b | −15 to −10°F | 380 | Des Moines, Cedar Rapids, Davenport, Ankeny |
| Zone 6a | −10 to −5°F | 33 | Burlington, Fort Madison, Keokuk, Glenwood |
Growing zone and frost dates by city
| City | Zone | Frost dates |
|---|---|---|
| Des Moines | 5b (−15 to −10°F) | Des Moines frost dates |
| Cedar Rapids | 5b (−15 to −10°F) | Cedar Rapids frost dates |
| Davenport | 5b (−15 to −10°F) | Davenport frost dates |
| Sioux City | 5a (−20 to −15°F) | Sioux City frost dates |
| Ankeny | 5b (−15 to −10°F) | Ankeny frost dates |
| Iowa City | 5b (−15 to −10°F) | Iowa City frost dates |
| West Des Moines | 5b (−15 to −10°F) | West Des Moines frost dates |
| Ames | 5b (−15 to −10°F) | Ames frost dates |
| Waterloo | 5a (−20 to −15°F) | Waterloo frost dates |
| Council Bluffs | 5b (−15 to −10°F) | Council Bluffs frost dates |
| Dubuque | 5a (−20 to −15°F) | Dubuque frost dates |
| Urbandale | 5b (−15 to −10°F) | Urbandale frost dates |
| Marion | 5a (−20 to −15°F) | Marion frost dates |
| Cedar Falls | 5a (−20 to −15°F) | Cedar Falls frost dates |
| Bettendorf | 5b (−15 to −10°F) | Bettendorf frost dates |
| Waukee | 5b (−15 to −10°F) | Waukee frost dates |
| Marshalltown | 5a (−20 to −15°F) | Marshalltown frost dates |
| Mason City | 5a (−20 to −15°F) | Mason City frost dates |
| Ottumwa | 5b (−15 to −10°F) | Ottumwa frost dates |
| Johnston | 5b (−15 to −10°F) | Johnston frost dates |
| Fort Dodge | 5a (−20 to −15°F) | Fort Dodge frost dates |
| Clinton | 5b (−15 to −10°F) | Clinton frost dates |
| Coralville | 5b (−15 to −10°F) | Coralville frost dates |
| Burlington | 6a (−10 to −5°F) | Burlington frost dates |
| Muscatine | 5b (−15 to −10°F) | Muscatine frost dates |
| Altoona | 5b (−15 to −10°F) | Altoona frost dates |
| North Liberty | 5b (−15 to −10°F) | North Liberty frost dates |
| Clive | 5b (−15 to −10°F) | Clive frost dates |
| Grimes | 5b (−15 to −10°F) | Grimes frost dates |
| Indianola | 5b (−15 to −10°F) | Indianola frost dates |
| Newton | 5b (−15 to −10°F) | Newton frost dates |
| Norwalk | 5b (−15 to −10°F) | Norwalk frost dates |
| Boone | 5a (−20 to −15°F) | Boone frost dates |
| Storm Lake | 5a (−20 to −15°F) | Storm Lake frost dates |
| Oskaloosa | 5b (−15 to −10°F) | Oskaloosa frost dates |
| Pleasant Hill | 5b (−15 to −10°F) | Pleasant Hill frost dates |
| Spencer | 5a (−20 to −15°F) | Spencer frost dates |
| Pella | 5b (−15 to −10°F) | Pella frost dates |
| Le Mars | 5a (−20 to −15°F) | Le Mars frost dates |
| Waverly | 5a (−20 to −15°F) | Waverly frost dates |
| Carroll | 5a (−20 to −15°F) | Carroll frost dates |
| Fort Madison | 6a (−10 to −5°F) | Fort Madison frost dates |
| Bondurant | 5b (−15 to −10°F) | Bondurant frost dates |
| Keokuk | 6a (−10 to −5°F) | Keokuk frost dates |
| Grinnell | 5b (−15 to −10°F) | Grinnell frost dates |
| Fairfield | 5b (−15 to −10°F) | Fairfield frost dates |
| Sioux Center | 5a (−20 to −15°F) | Sioux Center frost dates |
| Mount Pleasant | 5b (−15 to −10°F) | Mount Pleasant frost dates |
| Denison | 5a (−20 to −15°F) | Denison frost dates |
| Perry | 5a (−20 to −15°F) | Perry frost dates |
| Webster City | 5a (−20 to −15°F) | Webster City frost dates |
| Clear Lake | 5a (−20 to −15°F) | Clear Lake frost dates |
| Knoxville | 5b (−15 to −10°F) | Knoxville frost dates |
| Hiawatha | 5a (−20 to −15°F) | Hiawatha frost dates |
| Decorah | 5a (−20 to −15°F) | Decorah frost dates |
| Creston | 5b (−15 to −10°F) | Creston frost dates |
| Washington | 5b (−15 to −10°F) | Washington frost dates |
| Tiffin | 5b (−15 to −10°F) | Tiffin frost dates |
| Adel | 5b (−15 to −10°F) | Adel frost dates |
| Charles City | 5a (−20 to −15°F) | Charles City frost dates |
| Nevada | 5b (−15 to −10°F) | Nevada frost dates |
| Eldridge | 5b (−15 to −10°F) | Eldridge frost dates |
| Atlantic | 5a (−20 to −15°F) | Atlantic frost dates |
| Polk City | 5b (−15 to −10°F) | Polk City frost dates |
| Orange City | 5a (−20 to −15°F) | Orange City frost dates |
| Independence | 5a (−20 to −15°F) | Independence frost dates |
| Asbury | 5a (−20 to −15°F) | Asbury frost dates |
| Maquoketa | 5a (−20 to −15°F) | Maquoketa frost dates |
| Anamosa | 5a (−20 to −15°F) | Anamosa frost dates |
| Estherville | 5a (−20 to −15°F) | Estherville frost dates |
| Oelwein | 5a (−20 to −15°F) | Oelwein frost dates |
| DeWitt | 5b (−15 to −10°F) | DeWitt frost dates |
| Osceola | 5b (−15 to −10°F) | Osceola frost dates |
| Sheldon | 5a (−20 to −15°F) | Sheldon frost dates |
| Spirit Lake | 5a (−20 to −15°F) | Spirit Lake frost dates |
| Winterset | 5b (−15 to −10°F) | Winterset frost dates |
| Red Oak | 5b (−15 to −10°F) | Red Oak frost dates |
| Manchester | 5a (−20 to −15°F) | Manchester frost dates |
| Centerville | 5b (−15 to −10°F) | Centerville frost dates |
| Sergeant Bluff | 5a (−20 to −15°F) | Sergeant Bluff frost dates |
| Algona | 5a (−20 to −15°F) | Algona frost dates |
| Glenwood | 6a (−10 to −5°F) | Glenwood frost dates |
| Clarinda | 5b (−15 to −10°F) | Clarinda frost dates |
| Cherokee | 5a (−20 to −15°F) | Cherokee frost dates |
| Windsor Heights | 5b (−15 to −10°F) | Windsor Heights frost dates |
| Iowa Falls | 5a (−20 to −15°F) | Iowa Falls frost dates |
| Vinton | 5a (−20 to −15°F) | Vinton frost dates |
Frequently asked questions
What growing zone is Iowa in?
Iowa’s ZIP codes span USDA zones 4b to 6a, and 5a is the most common. Zones vary with elevation and distance from water, so check your own ZIP code.
When should I plant?
Hardiness zones are about winter cold, not planting dates. For timing, use the last spring frost date for your city on our Iowa frost dates page.