Johnsville, California has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from 33.4 °F (low) to 61.8 °F (high). Annual precipitation averages 58.3 Inches. Johnsville is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Jun. 11 - Jun. 20 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 22.5 °F | 44.1 °F | 10.56 in. |
| February | 22.8 °F | 46.3 °F | 9.27 in. |
| March | 26.3 °F | 50.7 °F | 8.89 in. |
| April | 29.6 °F | 56.8 °F | 5.08 in. |
| May | 36.3 °F | 65.4 °F | 3.18 in. |
| June | 42.5 °F | 74.6 °F | 1.02 in. |
| July | 48.3 °F | 83.3 °F | 0.17 in. |
| August | 47.2 °F | 82.6 °F | 0.19 in. |
| September | 41.6 °F | 78.2 °F | 0.69 in. |
| October | 34.1 °F | 65.3 °F | 2.92 in. |
| November | 26.7 °F | 51.2 °F | 5.44 in. |
| December | 22.5 °F | 42.7 °F | 10.86 in. |
| Annual | 33.4 °F | 61.8 °F | 58.27 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | Jun. 11 - Jun. 20 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 7a : 0°F to 5°F |
| Plant Hardiness Zone - 2012 | Zone 7b : 5°F to 10°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dsb - Humid Continental Climate - Dry Cool Summer |