Oregon frost dates: B
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Baker City | May 25 | Sep 15 | 113 d | 6b |
| Bandon | Mar 9 | Nov 27 | 263 d | 9b |
| Banks | Apr 16 | Oct 26 | 193 d | 8b |
| Bates | frost any month | 6b | ||
| Bay City | Apr 22 | Oct 21 | 182 d | 9a |
| Beatty | May 31 | Sep 21 | 113 d | 6a |
| Beaver | Mar 17 | Nov 22 | 250 d | 8b |
| Beavercreek | Mar 16 | Nov 19 | 248 d | 8b |
| Beaverton | Feb 11 | Dec 5 | 297 d | 8b |
| Bend | Jun 6 | Sep 20 | 106 d | 6b |
| Bend (Deschutes) | frost any month | 6a | ||
| Blachly | Apr 18 | Oct 25 | 190 d | 8b |
| Blodgett | May 15 | Oct 8 | 146 d | 8b |
| Blue River | May 1 | Oct 10 | 162 d | 7b |
| Bly | May 31 | Sep 21 | 113 d | 6b |
| Boardman | Apr 14 | Oct 21 | 190 d | 7b |
| Bonanza | May 31 | Sep 21 | 113 d | 6b |
| Boring | Mar 16 | Nov 20 | 249 d | 8b |
| Bridal Veil | Apr 29 | Oct 22 | 176 d | 9a |
| Bridgeport | May 25 | Sep 15 | 113 d | 6b |
| Brightwood | Mar 27 | Nov 18 | 236 d | 8a |
| Broadbent | Mar 21 | Nov 14 | 238 d | 9a |
| Brogan | May 7 | Oct 3 | 149 d | 6b |
| Brookings | Jan 31 | Dec 27 | 330 d | 9b |
| Brothers | frost any month | 6a | ||
| Brownsville | Mar 14 | Nov 18 | 249 d | 8b |
| Burns | Jun 11 | Sep 6 | 87 d | 6a |
| Butte Falls | Apr 29 | Oct 17 | 171 d | 8a |
| Buxton | May 8 | Oct 1 | 146 d | 8b |