Glendora, California has a Hot-Summer Mediterranean Climate climate (Köppen classification: Csa). Average annual temperatures range from 11.8 °C (low) to 25.6 °C (high). Annual precipitation averages 492 Millimeters. Glendora is located in USDA Plant Hardiness Zone 10a.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 7.5 °C | 20.2 °C | 112.52 mm |
| February | 7.8 °C | 20.4 °C | 124.46 mm |
| March | 8.8 °C | 21.9 °C | 80.52 mm |
| April | 10.1 °C | 23.5 °C | 24.89 mm |
| May | 12.4 °C | 25.4 °C | 14.48 mm |
| June | 14.4 °C | 28.2 °C | 4.83 mm |
| July | 16.7 °C | 31.8 °C | 2.03 mm |
| August | 17.1 °C | 32.8 °C | 0.25 mm |
| September | 16.2 °C | 31.7 °C | 4.57 mm |
| October | 13.4 °C | 27.9 °C | 20.57 mm |
| November | 9.8 °C | 23.7 °C | 26.16 mm |
| December | 7.1 °C | 19.7 °C | 76.71 mm |
| Annual | 11.8 °C | 25.6 °C | 491.99 mm |
| Average First Frost Date | Frost Rare |
| Average Last Frost Date | |
| Average Days With Frost | Frost Rare |
| Plant Hardiness Zone | Zone 10a : -1.1°C to 1.7°C |
| Plant Hardiness Zone - 2012 | Zone 10a : -1.1°C to 1.7°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Csa - Hot-Summer Mediterranean Climate |