Downey, California has a Hot-Summer Mediterranean Climate climate (Köppen classification: Csa). Average annual temperatures range from 55.5 °F (low) to 75.1 °F (high). Annual precipitation averages 13.8 Inches. Downey is located in USDA Plant Hardiness Zone 10b.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 47.2 °F | 67.7 °F | 3.22 in. |
| February | 48.5 °F | 67.6 °F | 3.51 in. |
| March | 50.9 °F | 68.9 °F | 2.24 in. |
| April | 53.1 °F | 72.9 °F | 0.76 in. |
| May | 57.2 °F | 74.6 °F | 0.24 in. |
| June | 60.7 °F | 77.9 °F | 0.07 in. |
| July | 63.9 °F | 82.9 °F | 0.05 in. |
| August | 64.5 °F | 84.7 °F | 0.01 in. |
| September | 63.1 °F | 83.8 °F | 0.11 in. |
| October | 58.5 °F | 79.5 °F | 0.51 in. |
| November | 51.7 °F | 72.8 °F | 0.83 in. |
| December | 46.7 °F | 67.3 °F | 2.27 in. |
| Annual | 55.5 °F | 75.1 °F | 13.82 in. |
| Average First Frost Date | No Frost |
| Average Last Frost Date | |
| Average Days With Frost | Frost Free |
| Plant Hardiness Zone | Zone 10b : 35°F to 30°F |
| Plant Hardiness Zone - 2012 | Zone 10b : 35°F to 30°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Csa - Hot-Summer Mediterranean Climate |