Langley, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 43.1 °F (low) to 59 °F (high). Annual precipitation averages 31.8 Inches. 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 | 35.9 °F | 46.5 °F | 3.79 in. |
| February | 35.6 °F | 48.6 °F | 3.29 in. |
| March | 37.8 °F | 52.5 °F | 3.6 in. |
| April | 41.0 °F | 57.2 °F | 2.57 in. |
| May | 45.8 °F | 63.6 °F | 1.98 in. |
| June | 49.7 °F | 68.0 °F | 1.54 in. |
| July | 52.0 °F | 73.2 °F | 0.93 in. |
| August | 52.0 °F | 74.2 °F | 0.85 in. |
| September | 49.0 °F | 68.6 °F | 1.4 in. |
| October | 43.8 °F | 58.7 °F | 2.79 in. |
| November | 39.0 °F | 51.0 °F | 4.86 in. |
| December | 35.6 °F | 45.7 °F | 4.2 in. |
| Annual | 43.1 °F | 59 °F | 31.8 in. |
| 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 : 15°F to 20°F |
| Plant Hardiness Zone - 2012 | Zone 8b : 15°F to 20°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |