Junction City, California has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 4.9 °C (low) to 21.6 °C (high). Annual precipitation averages 878.3 Millimeters. Junction City is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 0.5 °C | 9.3 °C | 166.12 mm |
| February | 0.6 °C | 12.6 °C | 134.11 mm |
| March | 1.6 °C | 16.1 °C | 119.89 mm |
| April | 3 °C | 19.7 °C | 52.58 mm |
| May | 6.1 °C | 24.8 °C | 35.56 mm |
| June | 8.8 °C | 29.7 °C | 20.07 mm |
| July | 12.2 °C | 35.3 °C | 4.83 mm |
| August | 11.2 °C | 35.1 °C | 4.06 mm |
| September | 8.1 °C | 31.5 °C | 7.87 mm |
| October | 4.2 °C | 23.4 °C | 39.62 mm |
| November | 2.3 °C | 13.6 °C | 99.82 mm |
| December | 0.3 °C | 8.2 °C | 193.8 mm |
| Annual | 4.9 °C | 21.6 °C | 878.33 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 8b : -9.4°C to -6.7°C |
| Plant Hardiness Zone - 2012 | Zone 8b : -9.4°C to -6.7°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |