Stanwood, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 5.8 °C (low) to 14.7 °C (high). Annual precipitation averages 840.7 Millimeters. Stanwood 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 | 1.7 °C | 8 °C | 100.58 mm |
| February | 1.6 °C | 9 °C | 75.18 mm |
| March | 2.9 °C | 11.3 °C | 92.71 mm |
| April | 4.8 °C | 13.9 °C | 71.63 mm |
| May | 7.4 °C | 17.2 °C | 61.47 mm |
| June | 9.7 °C | 19.5 °C | 37.34 mm |
| July | 10.9 °C | 22.3 °C | 25.65 mm |
| August | 10.9 °C | 22.8 °C | 27.43 mm |
| September | 9 °C | 20 °C | 46.74 mm |
| October | 5.9 °C | 14.9 °C | 76.71 mm |
| November | 3.5 °C | 10.6 °C | 120.9 mm |
| December | 1.6 °C | 7.4 °C | 104.39 mm |
| Annual | 5.8 °C | 14.7 °C | 840.73 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 |