Nebraska frost dates: O
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Oak | Apr 29 | Oct 10 | 164 d | 6a |
| Oakdale | May 4 | Oct 4 | 153 d | 5a |
| Oakland | Apr 28 | Oct 12 | 167 d | 5b |
| Oconto | May 10 | Oct 1 | 144 d | 5a |
| Odell | Apr 25 | Oct 13 | 171 d | 6a |
| Odessa | Apr 30 | Oct 10 | 163 d | 5b |
| Offutt Afb | Apr 18 | Oct 21 | 186 d | 5b |
| Ogallala | May 1 | Oct 12 | 164 d | 5b |
| Ohiowa | Apr 20 | Oct 18 | 181 d | 6a |
| Omaha | Apr 18 | Oct 21 | 186 d | 6a |
| Oneill | May 3 | Oct 5 | 155 d | 5b |
| Ong | Apr 19 | Oct 20 | 184 d | 6a |
| Orchard | May 7 | Sep 30 | 146 d | 5a |
| Ord | May 5 | Oct 3 | 151 d | 5b |
| Orleans | Apr 25 | Oct 14 | 172 d | 6a |
| Osceola | Apr 25 | Oct 14 | 172 d | 5b |
| Oshkosh | May 9 | Oct 2 | 146 d | 5b |
| Osmond | Apr 30 | Oct 6 | 159 d | 5a |
| Otoe | Apr 25 | Oct 11 | 169 d | 6a |
| Overton | Apr 26 | Oct 13 | 170 d | 5b |
| Oxford | May 1 | Oct 8 | 160 d | 6a |