Illinois frost dates: W
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Wadsworth | Apr 30 | Oct 21 | 174 d | 5b |
| Waggoner | Apr 12 | Oct 20 | 191 d | 6a |
| Walnut | Apr 24 | Oct 14 | 173 d | 5b |
| Walnut Hill | Apr 9 | Oct 24 | 198 d | 6b |
| Walsh | Apr 8 | Oct 30 | 205 d | 7a |
| Walshville | Apr 13 | Oct 24 | 194 d | 6b |
| Waltonville | Apr 4 | Oct 27 | 206 d | 6b |
| Wapella | Apr 21 | Oct 20 | 182 d | 6a |
| Warren | Apr 27 | Oct 9 | 165 d | 5a |
| Warrensburg | Apr 14 | Oct 24 | 193 d | 6a |
| Warrenville | Apr 28 | Oct 16 | 171 d | 5b |
| Warsaw | Apr 10 | Oct 27 | 200 d | 6a |
| Wasco | Apr 25 | Oct 19 | 177 d | 5b |
| Washburn | Apr 20 | Oct 17 | 180 d | 5b |
| Washington | Apr 21 | Oct 17 | 179 d | 6a |
| Wataga | Apr 20 | Oct 19 | 182 d | 5b |
| Waterloo | Apr 9 | Oct 26 | 200 d | 7a |
| Waterman | Apr 28 | Oct 10 | 165 d | 5b |
| Watseka | Apr 24 | Oct 16 | 175 d | 5b |
| Watson | Apr 13 | Oct 24 | 194 d | 6b |
| Wauconda | Apr 29 | Oct 20 | 174 d | 5b |
| Waukegan | Apr 30 | Oct 19 | 172 d | 6a |
| Waverly | Apr 7 | Oct 29 | 205 d | 6a |
| Wayne | Apr 25 | Oct 19 | 177 d | 5b |
| Wayne City | Apr 7 | Oct 26 | 202 d | 6b |
| Waynesville | Apr 20 | Oct 16 | 179 d | 6a |
| Wedron | Apr 27 | Oct 17 | 173 d | 5b |
| Weldon | Apr 16 | Oct 22 | 189 d | 6a |
| Wellington | Apr 22 | Oct 19 | 180 d | 6a |
| Wenona | Apr 26 | Oct 17 | 174 d | 5b |
| West Brooklyn | Apr 27 | Oct 12 | 168 d | 5b |
| West Chicago | Apr 25 | Oct 19 | 177 d | 5b |
| West Frankfort | Apr 4 | Oct 28 | 207 d | 7a |
| West Liberty | Apr 13 | Oct 22 | 192 d | 6b |
| West Point | Apr 13 | Oct 22 | 192 d | 6a |
| West Salem | Apr 4 | Oct 28 | 207 d | 6b |
| West Union | Apr 8 | Oct 27 | 202 d | 6b |
| West York | Apr 13 | Oct 22 | 192 d | 6b |
| Westchester | Apr 11 | Oct 31 | 203 d | 6a |
| Western Springs | Apr 19 | Oct 22 | 186 d | 6a |
| Westfield | Apr 15 | Oct 23 | 191 d | 6a |
| Westmont | Apr 28 | Oct 16 | 171 d | 6a |
| Westville | Apr 21 | Oct 20 | 182 d | 6a |
| Wheaton | Apr 28 | Oct 16 | 171 d | 5b |
| Wheeler | Apr 13 | Oct 22 | 192 d | 6b |
| Wheeling | Apr 19 | Oct 26 | 190 d | 6a |
| White Hall | Apr 13 | Oct 22 | 192 d | 6a |
| White Heath | Apr 23 | Oct 13 | 173 d | 6a |
| Whittington | Apr 4 | Oct 28 | 207 d | 6b |
| Williamsfield | Apr 21 | Oct 20 | 182 d | 5b |
| Williamsville | Apr 14 | Oct 20 | 189 d | 6a |
| Willisville | Apr 12 | Oct 22 | 193 d | 7a |
| Willow Hill | Apr 13 | Oct 22 | 192 d | 6b |
| Willow Springs | Apr 19 | Oct 22 | 186 d | 6a |
| Willowbrook | Apr 19 | Oct 22 | 186 d | 6a |
| Wilmette | Apr 26 | Oct 21 | 178 d | 6a |
| Wilmington | Apr 16 | Oct 26 | 193 d | 5b |
| Wilsonville | Apr 14 | Oct 21 | 190 d | 6b |
| Winchester | Apr 18 | Oct 20 | 185 d | 6a |
| Windsor | Apr 16 | Oct 22 | 189 d | 6a |
| Winfield | Apr 25 | Oct 19 | 177 d | 5b |
| Winnebago | Apr 24 | Oct 17 | 176 d | 5b |
| Winnetka | Apr 26 | Oct 21 | 178 d | 6a |
| Winslow | Apr 27 | Oct 14 | 170 d | 5a |
| Winthrop Harbor | Apr 30 | Oct 21 | 174 d | 6a |
| Witt | Apr 13 | Oct 24 | 194 d | 6b |
| Wolf Lake | Apr 8 | Oct 29 | 204 d | 7a |
| Wonder Lake | May 1 | Oct 11 | 163 d | 5b |
| Wood Dale | Apr 16 | Oct 28 | 195 d | 6a |
| Wood River | Apr 4 | Nov 5 | 215 d | 7a |
| Woodhull | Apr 28 | Oct 12 | 167 d | 5b |
| Woodland | Apr 24 | Oct 16 | 175 d | 5b |
| Woodlawn | Apr 9 | Oct 24 | 198 d | 6b |
| Woodridge | Apr 28 | Oct 16 | 171 d | 6a |
| Woodson | Apr 17 | Oct 21 | 187 d | 6a |
| Woodstock | Apr 25 | Oct 22 | 180 d | 5b |
| Woosung | Apr 21 | Oct 19 | 181 d | 5b |
| Worden | Apr 4 | Nov 5 | 215 d | 6b |
| Worth | Apr 10 | Nov 1 | 205 d | 6a |
| Wrights | Apr 13 | Oct 22 | 192 d | 6a |
| Wyanet | Apr 22 | Oct 17 | 178 d | 5b |
| Wyoming | Apr 22 | Oct 14 | 175 d | 5b |