Langley, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 6.2 °C (low) to 15 °C (high). Annual precipitation averages 807.7 Millimeters. Langley is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 2.2 °C | 8.1 °C | 96.27 mm |
| February | 2 °C | 9.2 °C | 83.57 mm |
| March | 3.2 °C | 11.4 °C | 91.44 mm |
| April | 5 °C | 14 °C | 65.28 mm |
| May | 7.7 °C | 17.6 °C | 50.29 mm |
| June | 9.8 °C | 20 °C | 39.12 mm |
| July | 11.1 °C | 22.9 °C | 23.62 mm |
| August | 11.1 °C | 23.4 °C | 21.59 mm |
| September | 9.4 °C | 20.3 °C | 35.56 mm |
| October | 6.6 °C | 14.8 °C | 70.87 mm |
| November | 3.9 °C | 10.6 °C | 123.44 mm |
| December | 2 °C | 7.6 °C | 106.68 mm |
| Annual | 6.2 °C | 15 °C | 807.73 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 40-50 Days |
| Plant Hardiness Zone | Zone 8b : -9.4°C to -6.7°C |
| Plant Hardiness Zone - 2012 | Zone 8b : -9.4°C to -6.7°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |