Marysville, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 5.9 °C (low) to 15.6 °C (high). Annual precipitation averages 1002.6 Millimeters. Marysville 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 | 1.4 °C | 8.1 °C | 128.02 mm |
| February | 1.4 °C | 9.7 °C | 92.46 mm |
| March | 2.8 °C | 11.9 °C | 104.39 mm |
| April | 4.7 °C | 15.2 °C | 86.36 mm |
| May | 7.6 °C | 18.6 °C | 67.06 mm |
| June | 9.9 °C | 20.7 °C | 57.91 mm |
| July | 11.4 °C | 23.8 °C | 23.88 mm |
| August | 11.3 °C | 24.1 °C | 23.62 mm |
| September | 9.2 °C | 21.5 °C | 50.04 mm |
| October | 5.9 °C | 15.7 °C | 101.35 mm |
| November | 3.3 °C | 10.8 °C | 141.48 mm |
| December | 1.4 °C | 7.6 °C | 125.98 mm |
| Annual | 5.9 °C | 15.6 °C | 1002.55 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 |