Iowa frost dates: W
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Wadena | May 4 | Oct 4 | 153 d | 5a |
| Walcott | Apr 23 | Oct 15 | 175 d | 5b |
| Walford | Apr 27 | Oct 11 | 167 d | 5a |
| Walker | May 3 | Oct 7 | 157 d | 5a |
| Wall Lake | Apr 30 | Oct 6 | 159 d | 5a |
| Wallingford | May 2 | Oct 3 | 154 d | 5a |
| Walnut | Apr 30 | Oct 2 | 155 d | 5a |
| Wapello | Apr 14 | Oct 24 | 193 d | 5b |
| Washington | Apr 28 | Oct 11 | 166 d | 5b |
| Washta | Apr 30 | Oct 9 | 162 d | 5a |
| Waterloo | Apr 27 | Oct 10 | 166 d | 5a |
| Waterville | May 2 | Oct 11 | 162 d | 5a |
| Watkins | Apr 27 | Oct 11 | 167 d | 5a |
| Waucoma | May 2 | Oct 5 | 156 d | 5a |
| Waukee | Apr 18 | Oct 20 | 185 d | 5b |
| Waukon | May 2 | Oct 11 | 162 d | 5a |
| Waverly | Apr 29 | Oct 9 | 163 d | 5a |
| Wayland | Apr 28 | Oct 11 | 166 d | 5b |
| Webb | Apr 30 | Oct 5 | 158 d | 5a |
| Webster | Apr 24 | Oct 15 | 174 d | 5b |
| Webster City | May 3 | Oct 2 | 152 d | 5a |
| Weldon | Apr 29 | Oct 9 | 163 d | 5b |
| Wellman | Apr 28 | Oct 11 | 166 d | 5b |
| Wellsburg | Apr 27 | Oct 10 | 166 d | 5a |
| Welton | Apr 25 | Oct 14 | 172 d | 5b |
| Wesley | Apr 30 | Oct 6 | 159 d | 5a |
| West Bend | Apr 30 | Oct 6 | 159 d | 5a |
| West Branch | Apr 29 | Oct 9 | 163 d | 5b |
| West Burlington | Apr 15 | Oct 20 | 188 d | 6a |
| West Chester | Apr 28 | Oct 11 | 166 d | 5b |
| West Des Moines | Apr 18 | Oct 20 | 185 d | 5b |
| West Liberty | Apr 29 | Oct 9 | 163 d | 5b |
| West Point | Apr 17 | Oct 22 | 188 d | 6a |
| West Union | May 4 | Oct 4 | 153 d | 5a |
| Westfield | Apr 30 | Oct 4 | 157 d | 5a |
| Westgate | Apr 27 | Oct 13 | 169 d | 5a |
| Westphalia | Apr 27 | Oct 9 | 165 d | 5b |
| Westside | Apr 27 | Oct 11 | 167 d | 5a |
| Wever | Apr 18 | Oct 20 | 185 d | 6a |
| What Cheer | Apr 24 | Oct 15 | 174 d | 5b |
| Wheatland | Apr 27 | Oct 10 | 166 d | 5a |
| Whiting | May 1 | Oct 3 | 155 d | 5a |
| Whittemore | Apr 30 | Oct 6 | 159 d | 5a |
| Whitten | Apr 27 | Oct 10 | 166 d | 5a |
| Williams | May 3 | Oct 2 | 152 d | 5a |
| Williamsburg | Apr 28 | Oct 9 | 164 d | 5b |
| Williamson | May 5 | Oct 5 | 153 d | 5b |
| Wilton | Apr 18 | Oct 22 | 187 d | 5b |
| Windsor Heights | Apr 18 | Oct 20 | 185 d | 5b |
| Winfield | Apr 26 | Oct 10 | 167 d | 5b |
| Winterset | Apr 30 | Oct 3 | 156 d | 5b |
| Winthrop | Apr 30 | Oct 7 | 160 d | 5a |
| Wiota | Apr 30 | Oct 2 | 155 d | 5b |
| Woden | Apr 29 | Oct 7 | 161 d | 5a |
| Woodbine | Apr 29 | Oct 8 | 162 d | 5b |
| Woodburn | Apr 29 | Oct 9 | 163 d | 5b |
| Woodward | Apr 25 | Oct 10 | 168 d | 5a |
| Woolstock | May 3 | Oct 2 | 152 d | 5a |
| Worthington | Apr 28 | Oct 10 | 165 d | 5a |
| Wyoming | Apr 27 | Oct 10 | 166 d | 5a |