Watsonville, California has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 8.7 °C (low) to 18.9 °C (high). Annual precipitation averages 558.3 Millimeters. Watsonville is located in USDA Plant Hardiness Zone 9b.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 5.4 °C | 15.7 °C | 103.89 mm |
| February | 6.2 °C | 16 °C | 117.86 mm |
| March | 6.7 °C | 16.8 °C | 75.69 mm |
| April | 7.4 °C | 18.3 °C | 41.4 mm |
| May | 9.3 °C | 19.6 °C | 13.97 mm |
| June | 10.7 °C | 20.6 °C | 3.05 mm |
| July | 12.3 °C | 20.8 °C | 0.76 mm |
| August | 12.5 °C | 21.4 °C | 1.27 mm |
| September | 11.7 °C | 22.2 °C | 1.52 mm |
| October | 9.6 °C | 21.9 °C | 22.86 mm |
| November | 7.1 °C | 18.2 °C | 54.86 mm |
| December | 5.3 °C | 15.6 °C | 121.16 mm |
| Annual | 8.7 °C | 18.9 °C | 558.29 mm |
| Average First Frost Date | Frost Rare |
| Average Last Frost Date | |
| Average Days With Frost | Frost Rare |
| 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 | Normal |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |