Sierra City, California has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 3 °C (low) to 18.2 °C (high). Annual precipitation averages 1736.3 Millimeters. Sierra City is located in USDA Plant Hardiness Zone 7b. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -2.9 °C | 8 °C | 319.02 mm |
| February | -2.3 °C | 9.9 °C | 307.59 mm |
| March | -0.8 °C | 12.7 °C | 253.49 mm |
| April | 0.9 °C | 15.1 °C | 132.33 mm |
| May | 4.3 °C | 19.9 °C | 101.09 mm |
| June | 7.6 °C | 25.2 °C | 27.69 mm |
| July | 11.2 °C | 29.8 °C | 2.54 mm |
| August | 10.8 °C | 29.6 °C | 5.84 mm |
| September | 8.2 °C | 27.1 °C | 17.78 mm |
| October | 3.4 °C | 20.7 °C | 99.57 mm |
| November | -1 °C | 12.7 °C | 170.94 mm |
| December | -3 °C | 7.4 °C | 298.45 mm |
| Annual | 3 °C | 18.2 °C | 1736.33 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 21 - May 31 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 7b : -15°C to -12.2°C |
| Plant Hardiness Zone - 2012 | Zone 8a : -12.2°C to -9.4°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |