Fieldbrook, California has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 44.7 °F (low) to 60.7 °F (high). Annual precipitation averages 53.5 Inches. Fieldbrook is located in USDA Plant Hardiness Zone 9b. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Nov. 21 - Nov. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 39.8 °F | 55.0 °F | 9.07 in. |
| February | 40.0 °F | 56.1 °F | 7.34 in. |
| March | 40.9 °F | 57.0 °F | 7.69 in. |
| April | 42.5 °F | 58.2 °F | 4.8 in. |
| May | 45.9 °F | 61.0 °F | 2.34 in. |
| June | 48.7 °F | 63.7 °F | 1.33 in. |
| July | 51.7 °F | 65.4 °F | 0.28 in. |
| August | 51.7 °F | 67.2 °F | 0.24 in. |
| September | 48.8 °F | 67.9 °F | 0.92 in. |
| October | 45.2 °F | 64.6 °F | 3.1 in. |
| November | 42.0 °F | 58.5 °F | 6.16 in. |
| December | 39.3 °F | 54.3 °F | 10.26 in. |
| Annual | 44.7 °F | 60.7 °F | 53.53 in. |
| Average First Frost Date | Nov. 21 - Nov. 30 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 20-30 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 | Moderate Drought |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |