Marcus, Washington has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 37.5 °F (low) to 60.2 °F (high). Annual precipitation averages 18.9 Inches. Marcus is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 24.4 °F | 34.3 °F | 2.25 in. |
| February | 25.3 °F | 40.7 °F | 1.32 in. |
| March | 29.9 °F | 50.6 °F | 1.89 in. |
| April | 35.2 °F | 61.1 °F | 1.55 in. |
| May | 43.0 °F | 71.0 °F | 1.66 in. |
| June | 48.7 °F | 76.4 °F | 1.76 in. |
| July | 53.7 °F | 86.9 °F | 0.75 in. |
| August | 52.8 °F | 87.5 °F | 0.52 in. |
| September | 45.6 °F | 76.8 °F | 0.7 in. |
| October | 36.8 °F | 59.7 °F | 1.54 in. |
| November | 30.6 °F | 43.6 °F | 2.28 in. |
| December | 24.5 °F | 34.2 °F | 2.71 in. |
| Annual | 37.5 °F | 60.2 °F | 18.93 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 7a : 0°F to 5°F |
| Plant Hardiness Zone - 2012 | Zone 6b : -5°F to 0°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |