Tustin, California has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 54.4 °F (low) to 75.4 °F (high). Annual precipitation averages 12.9 Inches. Tustin is located in USDA Plant Hardiness Zone 10b.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 46.2 °F | 67.8 °F | 2.83 in. |
| February | 47.1 °F | 67.7 °F | 3.31 in. |
| March | 49.6 °F | 69.2 °F | 1.89 in. |
| April | 51.8 °F | 73.3 °F | 0.71 in. |
| May | 56.2 °F | 74.9 °F | 0.3 in. |
| June | 59.8 °F | 78.4 °F | 0.09 in. |
| July | 63.1 °F | 83.2 °F | 0.06 in. |
| August | 63.8 °F | 85.3 °F | 0.01 in. |
| September | 62.1 °F | 84.8 °F | 0.13 in. |
| October | 57.2 °F | 80.3 °F | 0.48 in. |
| November | 50.3 °F | 73.0 °F | 0.82 in. |
| December | 45.6 °F | 67.4 °F | 2.27 in. |
| Annual | 54.4 °F | 75.4 °F | 12.9 in. |
| Average First Frost Date | No Frost |
| Average Last Frost Date | |
| Average Days With Frost | Frost Free |
| Plant Hardiness Zone | Zone 10b : 35°F to 30°F |
| Plant Hardiness Zone - 2012 | Zone 10a : 30°F to 25°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |