San Lorenzo, California has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 10.1 °C (low) to 19.7 °C (high). Annual precipitation averages 467.9 Millimeters. San Lorenzo is located in USDA Plant Hardiness Zone 10a.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 6.1 °C | 14.4 °C | 79.25 mm |
| February | 7.1 °C | 16 °C | 90.42 mm |
| March | 8 °C | 17.5 °C | 69.6 mm |
| April | 9.1 °C | 18.7 °C | 40.39 mm |
| May | 10.9 °C | 20.2 °C | 15.75 mm |
| June | 12.4 °C | 22.6 °C | 4.83 mm |
| July | 13.7 °C | 23.6 °C | 0.25 mm |
| August | 14 °C | 23.8 °C | 0.76 mm |
| September | 13.6 °C | 24.5 °C | 2.54 mm |
| October | 11.7 °C | 22.6 °C | 16.76 mm |
| November | 8.2 °C | 18 °C | 54.1 mm |
| December | 5.9 °C | 14.6 °C | 93.22 mm |
| Annual | 10.1 °C | 19.7 °C | 467.87 mm |
| Average First Frost Date | Frost Rare |
| Average Last Frost Date | |
| Average Days With Frost | Frost Rare |
| Plant Hardiness Zone | Zone 10a : -1.1°C to 1.7°C |
| Plant Hardiness Zone - 2012 | Zone 10a : -1.1°C to 1.7°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |