Riverdale, California has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 49.1 °F (low) to 77 °F (high). Annual precipitation averages 8.4 Inches. Riverdale is located in USDA Plant Hardiness Zone 9a. The growing season typically runs from the last frost around Feb. 21 - Feb. 29 through the first frost around Nov. 21 - Nov. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 37.5 °F | 56.2 °F | 1.8 in. |
| February | 40.2 °F | 62.2 °F | 1.5 in. |
| March | 43.2 °F | 68.6 °F | 1.46 in. |
| April | 46.3 °F | 74.8 °F | 0.69 in. |
| May | 53.0 °F | 82.9 °F | 0.43 in. |
| June | 58.2 °F | 90.9 °F | 0.06 in. |
| July | 63.6 °F | 96.7 °F | 0.01 in. |
| August | 62.4 °F | 95.9 °F | 0.0 in. |
| September | 57.8 °F | 91.1 °F | 0.06 in. |
| October | 50.0 °F | 80.8 °F | 0.39 in. |
| November | 41.1 °F | 66.9 °F | 0.66 in. |
| December | 36.0 °F | 56.6 °F | 1.33 in. |
| Annual | 49.1 °F | 77 °F | 8.39 in. |
| Average First Frost Date | Nov. 21 - Nov. 30 |
| Average Last Frost Date | Feb. 21 - Feb. 29 |
| Average Days With Frost | 20-30 Days |
| Plant Hardiness Zone | Zone 9a : 20°F to 25°F |
| Plant Hardiness Zone - 2012 | Zone 9a : 20°F to 25°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |