Marcus, Washington has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3.1 °C (low) to 15.7 °C (high). Annual precipitation averages 480.8 Millimeters. 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 | -4.2 °C | 1.3 °C | 57.15 mm |
| February | -3.7 °C | 4.8 °C | 33.53 mm |
| March | -1.2 °C | 10.3 °C | 48.01 mm |
| April | 1.8 °C | 16.2 °C | 39.37 mm |
| May | 6.1 °C | 21.7 °C | 42.16 mm |
| June | 9.3 °C | 24.7 °C | 44.7 mm |
| July | 12.1 °C | 30.5 °C | 19.05 mm |
| August | 11.6 °C | 30.8 °C | 13.21 mm |
| September | 7.6 °C | 24.9 °C | 17.78 mm |
| October | 2.7 °C | 15.4 °C | 39.12 mm |
| November | -0.8 °C | 6.4 °C | 57.91 mm |
| December | -4.2 °C | 1.2 °C | 68.83 mm |
| Annual | 3.1 °C | 15.7 °C | 480.82 mm |
| 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 : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |