Fieldbrook, California has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 7 °C (low) to 16 °C (high). Annual precipitation averages 1359.7 Millimeters. 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 | 4.3 °C | 12.8 °C | 230.38 mm |
| February | 4.4 °C | 13.4 °C | 186.44 mm |
| March | 4.9 °C | 13.9 °C | 195.33 mm |
| April | 5.8 °C | 14.6 °C | 121.92 mm |
| May | 7.7 °C | 16.1 °C | 59.44 mm |
| June | 9.3 °C | 17.6 °C | 33.78 mm |
| July | 10.9 °C | 18.6 °C | 7.11 mm |
| August | 10.9 °C | 19.6 °C | 6.1 mm |
| September | 9.3 °C | 19.9 °C | 23.37 mm |
| October | 7.3 °C | 18.1 °C | 78.74 mm |
| November | 5.6 °C | 14.7 °C | 156.46 mm |
| December | 4.1 °C | 12.4 °C | 260.6 mm |
| Annual | 7 °C | 16 °C | 1359.67 mm |
| 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 : -3.9°C to -1.1°C |
| Plant Hardiness Zone - 2012 | Zone 9b : -3.9°C to -1.1°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |