Rancho Santa Margarita, California has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 11.8 °C (low) to 23.8 °C (high). Annual precipitation averages 431.3 Millimeters. Rancho Santa Margarita 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 Jan. 11 - Jan. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 8.8 °C | 19.4 °C | 80.26 mm |
| February | 8.3 °C | 19.3 °C | 116.08 mm |
| March | 8.9 °C | 20.5 °C | 65.02 mm |
| April | 9.7 °C | 21.4 °C | 28.7 mm |
| May | 11.7 °C | 22.6 °C | 9.4 mm |
| June | 13.5 °C | 25.4 °C | 4.57 mm |
| July | 15.8 °C | 29.2 °C | 4.06 mm |
| August | 16.4 °C | 30.3 °C | 0.51 mm |
| September | 15.8 °C | 29.2 °C | 3.05 mm |
| October | 13.7 °C | 25.8 °C | 19.56 mm |
| November | 10.8 °C | 22.8 °C | 33.27 mm |
| December | 8.5 °C | 19.1 °C | 66.8 mm |
| Annual | 11.8 °C | 23.8 °C | 431.28 mm |
| Average First Frost Date | Jan. 11 - Jan. 20 |
| 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 | BSk - Cold Semi-Arid Climate |