San Juan Bautista, California has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 7.7 °C (low) to 21.7 °C (high). Annual precipitation averages 481.8 Millimeters. San Juan Bautista 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 | 3.9 °C | 15.8 °C | 103.89 mm |
| February | 4.8 °C | 17.1 °C | 92.96 mm |
| March | 5.7 °C | 18.9 °C | 63.25 mm |
| April | 6.6 °C | 20.3 °C | 35.05 mm |
| May | 8.7 °C | 22.6 °C | 16.51 mm |
| June | 10.2 °C | 25 °C | 2.29 mm |
| July | 11.7 °C | 26.3 °C | 0.25 mm |
| August | 11.9 °C | 26.9 °C | 0.51 mm |
| September | 11 °C | 26.9 °C | 0.76 mm |
| October | 8.7 °C | 24.7 °C | 24.89 mm |
| November | 5.7 °C | 19.8 °C | 45.21 mm |
| December | 3.5 °C | 15.7 °C | 96.27 mm |
| Annual | 7.7 °C | 21.7 °C | 481.84 mm |
| 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 : -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 |