California frost dates: Y
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Yermo | Feb 19 | Nov 26 | 280 d | 9a |
| Yettem | Jan 23 | Dec 13 | 324 d | 9b |
| Yokuts | Jun 1 | Oct 7 | 128 d | 9a |
| Yolo | Feb 7 | Dec 5 | 301 d | 9b |
| Yorba Linda | rare frost | 10a | ||
| Yorkville | Mar 5 | Nov 21 | 261 d | 9b |
| Yosemite National Park | Apr 21 | Oct 27 | 189 d | 7a |
| Yountville | Mar 2 | Nov 27 | 270 d | 9b |
| Yreka | Apr 30 | Oct 18 | 171 d | 8a |
| Yuba City | Feb 11 | Nov 30 | 292 d | 9b |
| Yucaipa | Jan 27 | Dec 19 | 326 d | 9b |
| Yucca Valley | Mar 14 | Nov 28 | 259 d | 9a |