Diablo Grande, California has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 50.7 °F (low) to 72.7 °F (high). Annual precipitation averages 14.7 Inches. Diablo Grande is located in USDA Plant Hardiness Zone 9b. The growing season typically runs from the last frost around Mar. 1 - Mar. 10 through the first frost around Nov. 21 - Nov. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 40.5 °F | 54.9 °F | 3.34 in. |
| February | 42.6 °F | 58.1 °F | 3.02 in. |
| March | 44.8 °F | 63.2 °F | 2.11 in. |
| April | 47.1 °F | 68.7 °F | 0.83 in. |
| May | 52.4 °F | 76.9 °F | 0.58 in. |
| June | 57.7 °F | 84.7 °F | 0.09 in. |
| July | 62.6 °F | 91.8 °F | 0.0 in. |
| August | 62.0 °F | 91.2 °F | 0.02 in. |
| September | 59.5 °F | 86.7 °F | 0.08 in. |
| October | 53.5 °F | 76.9 °F | 0.67 in. |
| November | 45.6 °F | 63.8 °F | 1.27 in. |
| December | 40.2 °F | 55.2 °F | 2.64 in. |
| Annual | 50.7 °F | 72.7 °F | 14.65 in. |
| Average First Frost Date | Nov. 21 - Nov. 30 |
| Average Last Frost Date | Mar. 1 - Mar. 10 |
| Average Days With Frost | 10-20 Days |
| Plant Hardiness Zone | Zone 9b : 25°F to 20°F |
| Plant Hardiness Zone - 2012 | Zone 9b : 25°F to 20°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |