Garrett, Washington has a Hot-Summer Mediterranean Climate climate (Köppen classification: Csa). Average annual temperatures range from 5.5 °C (low) to 18.2 °C (high). Annual precipitation averages 396.5 Millimeters. Garrett is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -1.7 °C | 5.5 °C | 45.47 mm |
| February | -0.7 °C | 8.6 °C | 35.81 mm |
| March | 1.8 °C | 13.7 °C | 40.89 mm |
| April | 4.5 °C | 17.8 °C | 41.4 mm |
| May | 8.2 °C | 22.5 °C | 43.18 mm |
| June | 11.6 °C | 26.4 °C | 28.19 mm |
| July | 14.5 °C | 32.1 °C | 7.62 mm |
| August | 14.1 °C | 31.8 °C | 10.41 mm |
| September | 9.7 °C | 26.4 °C | 17.27 mm |
| October | 4.8 °C | 18.3 °C | 33.27 mm |
| November | 1 °C | 10.1 °C | 44.96 mm |
| December | -1.7 °C | 5.2 °C | 48.01 mm |
| Annual | 5.5 °C | 18.2 °C | 396.48 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 7a : -17.8°C to -15°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Csa - Hot-Summer Mediterranean Climate |