Allendale, California has a Hot-Summer Mediterranean Climate climate (Köppen classification: Csa). Average annual temperatures range from 9.4 °C (low) to 24.3 °C (high). Annual precipitation averages 647.5 Millimeters. 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 | 3.8 °C | 13.8 °C | 137.92 mm |
| February | 5 °C | 16.3 °C | 139.95 mm |
| March | 6.6 °C | 19.1 °C | 88.65 mm |
| April | 8.4 °C | 22.7 °C | 36.58 mm |
| May | 11.2 °C | 27.2 °C | 20.83 mm |
| June | 13.8 °C | 31.7 °C | 4.32 mm |
| July | 15.3 °C | 34.8 °C | 0 mm |
| August | 14.6 °C | 34.2 °C | 0.51 mm |
| September | 13.7 °C | 32.2 °C | 1.78 mm |
| October | 10.5 °C | 26.4 °C | 24.64 mm |
| November | 6.4 °C | 18.8 °C | 57.91 mm |
| December | 3.8 °C | 13.9 °C | 134.37 mm |
| Annual | 9.4 °C | 24.3 °C | 647.46 mm |
| 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 : -3.9°C to -1.1°C |
| Plant Hardiness Zone - 2012 | Zone 9b : -3.9°C to -1.1°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Csa - Hot-Summer Mediterranean Climate |