Allendale, California has a Hot-Summer Mediterranean Climate climate (Köppen classification: Csa). Average annual temperatures range from 49 °F (low) to 75.7 °F (high). Annual precipitation averages 25.5 Inches. Allendale 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 | 38.9 °F | 56.9 °F | 5.43 in. |
| February | 41.0 °F | 61.4 °F | 5.51 in. |
| March | 43.8 °F | 66.3 °F | 3.49 in. |
| April | 47.1 °F | 72.8 °F | 1.44 in. |
| May | 52.1 °F | 80.9 °F | 0.82 in. |
| June | 56.9 °F | 89.0 °F | 0.17 in. |
| July | 59.6 °F | 94.7 °F | 0.0 in. |
| August | 58.3 °F | 93.6 °F | 0.02 in. |
| September | 56.7 °F | 89.9 °F | 0.07 in. |
| October | 50.9 °F | 79.6 °F | 0.97 in. |
| November | 43.6 °F | 65.9 °F | 2.28 in. |
| December | 38.8 °F | 57.1 °F | 5.29 in. |
| Annual | 49 °F | 75.7 °F | 25.49 in. |
| Average First Frost Date | Dec. 1 - Dec. 10 |
| Average Last Frost Date | Feb. 11 - Feb. 20 |
| 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 | Csa - Hot-Summer Mediterranean Climate |