Atwater, California has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 49 °F (low) to 75.3 °F (high). Annual precipitation averages 12.8 Inches. Atwater is located in USDA Plant Hardiness Zone 9b. The growing season typically runs from the last frost around Feb. 11 - Feb. 20 through the first frost around Dec. 1 - Dec. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 38.3 °F | 55.2 °F | 2.76 in. |
| February | 40.6 °F | 61.1 °F | 2.31 in. |
| March | 43.6 °F | 66.7 °F | 1.99 in. |
| April | 46.5 °F | 72.6 °F | 1.0 in. |
| May | 52.2 °F | 81.3 °F | 0.57 in. |
| June | 57.5 °F | 89.1 °F | 0.14 in. |
| July | 61.7 °F | 94.7 °F | 0.01 in. |
| August | 60.5 °F | 93.5 °F | 0.0 in. |
| September | 57.3 °F | 89.3 °F | 0.05 in. |
| October | 50.4 °F | 79.1 °F | 0.67 in. |
| November | 42.2 °F | 65.4 °F | 1.08 in. |
| December | 37.3 °F | 55.7 °F | 2.21 in. |
| Annual | 49 °F | 75.3 °F | 12.79 in. |
| Average First Frost Date | Dec. 1 - Dec. 10 |
| Average Last Frost Date | Feb. 11 - Feb. 20 |
| Average Days With Frost | 20-30 Days |
| Plant Hardiness Zone | Zone 9b : 25°F to 20°F |
| Plant Hardiness Zone - 2012 | Zone 9a : 20°F to 25°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |