Tranquillity, California has a Cold Desert Climate climate (Köppen classification: BWk). Average annual temperatures range from 48.2 °F (low) to 76 °F (high). Annual precipitation averages 8.7 Inches. Tranquillity is located in USDA Plant Hardiness Zone 9a. 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 | 37.4 °F | 55.7 °F | 1.75 in. |
| February | 39.5 °F | 62.0 °F | 1.62 in. |
| March | 42.1 °F | 68.1 °F | 1.49 in. |
| April | 45.2 °F | 73.9 °F | 0.74 in. |
| May | 51.6 °F | 82.6 °F | 0.4 in. |
| June | 56.8 °F | 90.1 °F | 0.09 in. |
| July | 62.0 °F | 94.6 °F | 0.0 in. |
| August | 61.1 °F | 93.9 °F | 0.0 in. |
| September | 57.0 °F | 89.7 °F | 0.09 in. |
| October | 49.4 °F | 79.5 °F | 0.44 in. |
| November | 40.5 °F | 66.2 °F | 0.67 in. |
| December | 35.7 °F | 55.9 °F | 1.43 in. |
| Annual | 48.2 °F | 76 °F | 8.72 in. |
| Average First Frost Date | Nov. 21 - Nov. 30 |
| Average Last Frost Date | Feb. 21 - Feb. 29 |
| Average Days With Frost | 20-30 Days |
| Plant Hardiness Zone | Zone 9a : 20°F to 25°F |
| Plant Hardiness Zone - 2012 | Zone 9a : 20°F to 25°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | BWk - Cold Desert Climate |