Rosemead, California has a Hot-Summer Mediterranean Climate climate (Köppen classification: Csa). Average annual temperatures range from 55 °F (low) to 78.2 °F (high). Annual precipitation averages 16.4 Inches. Rosemead is located in USDA Plant Hardiness Zone 10a.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 46.7 °F | 69.2 °F | 3.76 in. |
| February | 47.8 °F | 69.2 °F | 4.29 in. |
| March | 50.0 °F | 71.3 °F | 2.73 in. |
| April | 52.5 °F | 76.1 °F | 0.89 in. |
| May | 56.8 °F | 77.7 °F | 0.39 in. |
| June | 60.4 °F | 82.6 °F | 0.12 in. |
| July | 63.9 °F | 87.6 °F | 0.03 in. |
| August | 64.6 °F | 89.7 °F | 0.01 in. |
| September | 62.9 °F | 88.6 °F | 0.14 in. |
| October | 57.9 °F | 82.6 °F | 0.59 in. |
| November | 51.0 °F | 74.9 °F | 0.78 in. |
| December | 45.8 °F | 68.4 °F | 2.62 in. |
| Annual | 55 °F | 78.2 °F | 16.35 in. |
| Average First Frost Date | Frost Rare |
| Average Last Frost Date | |
| Average Days With Frost | Frost Rare |
| Plant Hardiness Zone | Zone 10a : 30°F to 25°F |
| Plant Hardiness Zone - 2012 | Zone 10a : 30°F to 25°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Csa - Hot-Summer Mediterranean Climate |