Exeter, California has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 50 °F (low) to 76.8 °F (high). Annual precipitation averages 11.4 Inches. Exeter is located in USDA Plant Hardiness Zone 9b. The growing season typically runs from the last frost around Feb. 1 - Feb. 10 through the first frost around Dec. 11 - Dec. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 38.0 °F | 56.9 °F | 2.2 in. |
| February | 40.6 °F | 62.5 °F | 1.93 in. |
| March | 44.0 °F | 68.5 °F | 1.96 in. |
| April | 47.1 °F | 74.0 °F | 1.13 in. |
| May | 53.5 °F | 82.6 °F | 0.46 in. |
| June | 59.4 °F | 91.0 °F | 0.13 in. |
| July | 65.2 °F | 96.4 °F | 0.02 in. |
| August | 63.5 °F | 95.5 °F | 0.0 in. |
| September | 58.8 °F | 90.6 °F | 0.08 in. |
| October | 50.6 °F | 79.6 °F | 0.53 in. |
| November | 42.0 °F | 66.5 °F | 1.04 in. |
| December | 36.9 °F | 56.9 °F | 1.9 in. |
| Annual | 50 °F | 76.8 °F | 11.38 in. |
| Average First Frost Date | Dec. 11 - Dec. 20 |
| Average Last Frost Date | Feb. 1 - Feb. 10 |
| 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 | BSk - Cold Semi-Arid Climate |