Glendale, Oregon has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 4.7 °C (low) to 19 °C (high). Annual precipitation averages 1004.3 Millimeters. Glendale is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -0.4 °C | 8.3 °C | 169.16 mm |
| February | -0.1 °C | 12 °C | 122.43 mm |
| March | 1.2 °C | 14.6 °C | 118.11 mm |
| April | 3.3 °C | 16.9 °C | 79.5 mm |
| May | 6.2 °C | 21.8 °C | 48.77 mm |
| June | 8.9 °C | 25.7 °C | 22.61 mm |
| July | 12.2 °C | 31 °C | 9.14 mm |
| August | 11.7 °C | 31.3 °C | 7.37 mm |
| September | 8 °C | 27.6 °C | 18.54 mm |
| October | 3.6 °C | 20.2 °C | 63.75 mm |
| November | 1.6 °C | 11.9 °C | 147.07 mm |
| December | -0.3 °C | 7.2 °C | 197.87 mm |
| Annual | 4.7 °C | 19 °C | 1004.32 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 8b : -9.4°C to -6.7°C |
| Plant Hardiness Zone - 2012 | Zone 8a : -12.2°C to -9.4°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |