Granite Bay, California has a Hot-Summer Mediterranean Climate climate (Köppen classification: Csa). Average annual temperatures range from 49.5 °F (low) to 74.4 °F (high). Annual precipitation averages 26.3 Inches. Granite Bay is located in USDA Plant Hardiness Zone 9b. The growing season typically runs from the last frost around Feb. 21 - Feb. 29 through the first frost around Nov. 21 - Nov. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 39.2 °F | 55.7 °F | 4.82 in. |
| February | 41.1 °F | 60.2 °F | 4.7 in. |
| March | 44.1 °F | 65.0 °F | 3.9 in. |
| April | 46.4 °F | 70.8 °F | 2.11 in. |
| May | 51.8 °F | 79.1 °F | 1.43 in. |
| June | 57.7 °F | 87.6 °F | 0.3 in. |
| July | 61.7 °F | 94.1 °F | 0.01 in. |
| August | 60.9 °F | 93.8 °F | 0.03 in. |
| September | 57.6 °F | 88.4 °F | 0.16 in. |
| October | 50.9 °F | 77.8 °F | 1.37 in. |
| November | 43.3 °F | 64.3 °F | 2.62 in. |
| December | 38.7 °F | 55.9 °F | 4.88 in. |
| Annual | 49.5 °F | 74.4 °F | 26.33 in. |
| Average First Frost Date | Nov. 21 - Nov. 30 |
| Average Last Frost Date | Feb. 21 - Feb. 29 |
| 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 |