Thermal, California has a Hot Desert Climate climate (Köppen classification: BWh). Average annual temperatures range from 59.1 °F (low) to 87.3 °F (high). Annual precipitation averages 2.7 Inches. Thermal is located in USDA Plant Hardiness Zone 9b. The growing season typically runs from the last frost around Feb. 1 - Feb. 10 through the first frost around Dec. 1 - Dec. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 42.7 °F | 69.7 °F | 0.64 in. |
| February | 46.2 °F | 73.1 °F | 0.49 in. |
| March | 52.0 °F | 79.2 °F | 0.3 in. |
| April | 57.2 °F | 85.6 °F | 0.06 in. |
| May | 64.2 °F | 92.4 °F | 0.02 in. |
| June | 70.3 °F | 100.9 °F | 0.0 in. |
| July | 77.5 °F | 105.1 °F | 0.08 in. |
| August | 77.8 °F | 104.9 °F | 0.12 in. |
| September | 70.9 °F | 100.5 °F | 0.21 in. |
| October | 60.7 °F | 90.2 °F | 0.18 in. |
| November | 48.3 °F | 77.8 °F | 0.15 in. |
| December | 41.1 °F | 68.4 °F | 0.42 in. |
| Annual | 59.1 °F | 87.3 °F | 2.67 in. |
| Average First Frost Date | Dec. 1 - Dec. 10 |
| Average Last Frost Date | Feb. 1 - Feb. 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 | BWh - Hot Desert Climate |