Palermo, California has a Hot-Summer Mediterranean Climate climate (Köppen classification: Csa). Average annual temperatures range from 49.6 °F (low) to 74.9 °F (high). Annual precipitation averages 29.1 Inches. Palermo is located in USDA Plant Hardiness Zone 9b. The growing season typically runs from the last frost around Feb. 11 - Feb. 20 through the first frost around Dec. 11 - Dec. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 38.9 °F | 55.7 °F | 5.53 in. |
| February | 41.3 °F | 60.9 °F | 4.94 in. |
| March | 43.8 °F | 65.8 °F | 4.66 in. |
| April | 46.8 °F | 71.8 °F | 1.91 in. |
| May | 52.9 °F | 80.4 °F | 1.26 in. |
| June | 58.7 °F | 88.8 °F | 0.45 in. |
| July | 62.5 °F | 94.7 °F | 0.02 in. |
| August | 60.8 °F | 93.2 °F | 0.06 in. |
| September | 57.1 °F | 88.7 °F | 0.22 in. |
| October | 50.5 °F | 78.6 °F | 1.29 in. |
| November | 42.8 °F | 64.5 °F | 2.75 in. |
| December | 38.6 °F | 55.6 °F | 6.01 in. |
| Annual | 49.6 °F | 74.9 °F | 29.1 in. |
| Average First Frost Date | Dec. 11 - Dec. 20 |
| Average Last Frost Date | Feb. 11 - Feb. 20 |
| Average Days With Frost | 10-20 Days |
| Plant Hardiness Zone | Zone 9b : 25°F to 20°F |
| Plant Hardiness Zone - 2012 | Zone 9b : 25°F to 20°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Csa - Hot-Summer Mediterranean Climate |