Illinois frost dates: H
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Hagarstown | Apr 10 | Oct 24 | 197 d | 6b |
| Hamburg | Apr 20 | Oct 20 | 183 d | 6a |
| Hamel | Apr 4 | Nov 5 | 215 d | 6b |
| Hamilton | Apr 10 | Oct 27 | 200 d | 6a |
| Hammond | Apr 15 | Oct 20 | 188 d | 6a |
| Hampshire | Apr 26 | Oct 18 | 175 d | 5b |
| Hampton | Apr 16 | Oct 25 | 192 d | 5b |
| Hanna City | Apr 16 | Oct 23 | 190 d | 6a |
| Hanover | May 1 | Oct 9 | 161 d | 5a |
| Hanover Park | Apr 30 | Oct 13 | 166 d | 5b |
| Hardin | Apr 20 | Oct 20 | 183 d | 6b |
| Harmon | Apr 24 | Oct 14 | 173 d | 5b |
| Harrisburg | Apr 7 | Oct 26 | 202 d | 7a |
| Harristown | Apr 14 | Oct 24 | 193 d | 6a |
| Hartford | Apr 4 | Nov 5 | 215 d | 7a |
| Hartsburg | Apr 20 | Oct 16 | 179 d | 6a |
| Harvard | Apr 28 | Oct 12 | 167 d | 5b |
| Harvel | Apr 12 | Oct 20 | 191 d | 6a |
| Harvey | Apr 23 | Oct 20 | 180 d | 6a |
| Harwood Heights | Apr 16 | Oct 28 | 195 d | 6a |
| Havana | Apr 17 | Oct 19 | 185 d | 6a |
| Hazel Crest | Apr 23 | Oct 20 | 180 d | 6a |
| Hebron | Apr 30 | Oct 13 | 166 d | 5b |
| Hecker | Apr 12 | Oct 20 | 191 d | 7a |
| Henderson | Apr 20 | Oct 19 | 182 d | 5b |
| Hennepin | Apr 18 | Oct 22 | 187 d | 5b |
| Henning | Apr 22 | Oct 19 | 180 d | 6a |
| Henry | Apr 20 | Oct 17 | 180 d | 5b |
| Herod | Apr 19 | Oct 20 | 184 d | 7a |
| Herrick | Apr 15 | Oct 19 | 187 d | 6b |
| Herrin | Apr 9 | Oct 22 | 196 d | 7a |
| Herscher | Apr 19 | Oct 24 | 188 d | 5b |
| Hettick | Apr 14 | Oct 21 | 190 d | 6a |
| Heyworth | Apr 21 | Oct 20 | 182 d | 6a |
| Hickory Hills | Apr 19 | Oct 22 | 186 d | 6a |
| Hidalgo | Apr 13 | Oct 22 | 192 d | 6b |
| Highland | Apr 12 | Oct 20 | 191 d | 6b |
| Highland Park | Apr 26 | Oct 21 | 178 d | 6a |
| Highwood | Apr 26 | Oct 21 | 178 d | 6a |
| Hillsboro | Apr 13 | Oct 24 | 194 d | 6b |
| Hillsdale | Apr 16 | Oct 25 | 192 d | 5b |
| Hillside | Apr 16 | Oct 28 | 195 d | 6a |
| Hillview | Apr 13 | Oct 22 | 192 d | 6b |
| Hinckley | Apr 28 | Oct 13 | 168 d | 5b |
| Hindsboro | Apr 15 | Oct 20 | 188 d | 6a |
| Hines | Apr 11 | Oct 31 | 203 d | 6a |
| Hinsdale | Apr 28 | Oct 16 | 171 d | 6a |
| Hoffman | Apr 6 | Oct 29 | 206 d | 6b |
| Hoffman Estates | Apr 30 | Oct 13 | 166 d | 5b |
| Holcomb | Apr 24 | Oct 17 | 176 d | 5b |
| Homer | Apr 20 | Oct 21 | 184 d | 6a |
| Homer Glen | Apr 20 | Oct 22 | 185 d | 6a |
| Hometown | Apr 10 | Nov 1 | 205 d | 6a |
| Homewood | Apr 23 | Oct 20 | 180 d | 6a |
| Hoopeston | Apr 22 | Oct 19 | 180 d | 6a |
| Hooppole | Apr 20 | Oct 20 | 183 d | 5b |
| Hopedale | Apr 21 | Oct 17 | 179 d | 6a |
| Hopkins Park | Apr 19 | Oct 24 | 188 d | 5b |
| Hoyleton | Apr 7 | Oct 26 | 202 d | 6b |
| Hudson | Apr 25 | Oct 16 | 174 d | 6a |
| Huey | Apr 6 | Oct 29 | 206 d | 6b |
| Hull | Apr 4 | Nov 4 | 214 d | 6b |
| Humboldt | Apr 15 | Oct 24 | 192 d | 6a |
| Hume | Apr 19 | Oct 19 | 183 d | 6a |
| Huntley | Apr 25 | Oct 22 | 180 d | 5b |
| Huntsville | Apr 18 | Oct 21 | 186 d | 6a |
| Hurst | Apr 9 | Oct 22 | 196 d | 7a |
| Hutsonville | Apr 12 | Oct 22 | 193 d | 6b |