Rancho San Diego, California has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 12 °C (low) to 23.4 °C (high). Annual precipitation averages 318.8 Millimeters. Rancho San Diego is located in USDA Plant Hardiness Zone 10b. The growing season typically runs from the last frost around Frost Rare through the first frost around Dec. 21 - Dec. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 7.1 °C | 19.9 °C | 62.23 mm |
| February | 7.7 °C | 20.1 °C | 73.41 mm |
| March | 9.2 °C | 20.6 °C | 50.8 mm |
| April | 10.5 °C | 21.7 °C | 22.61 mm |
| May | 13.1 °C | 22.7 °C | 9.14 mm |
| June | 14.9 °C | 24.3 °C | 1.27 mm |
| July | 17 °C | 26.9 °C | 2.29 mm |
| August | 17.7 °C | 28.2 °C | 0.76 mm |
| September | 16.7 °C | 28.2 °C | 3.81 mm |
| October | 13.6 °C | 26.1 °C | 13.72 mm |
| November | 9.6 °C | 22.9 °C | 26.67 mm |
| December | 6.7 °C | 19.7 °C | 52.07 mm |
| Annual | 12 °C | 23.4 °C | 318.78 mm |
| Average First Frost Date | Dec. 21 - Dec. 31 |
| Average Last Frost Date | Frost Rare |
| Average Days With Frost | Frost Rare |
| Plant Hardiness Zone | Zone 10b : 1.7°C to 4.4°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 |