Malden, Washington has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from 2.5 °C (low) to 15.3 °C (high). Annual precipitation averages 451.4 Millimeters. Malden is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -3.9 °C | 2.8 °C | 54.86 mm |
| February | -3.2 °C | 5.4 °C | 40.64 mm |
| March | -1 °C | 9.9 °C | 46.99 mm |
| April | 1.5 °C | 14.4 °C | 38.86 mm |
| May | 5.1 °C | 19.5 °C | 40.64 mm |
| June | 8.2 °C | 23.1 °C | 33.27 mm |
| July | 10.5 °C | 29.4 °C | 12.95 mm |
| August | 10.2 °C | 29.6 °C | 10.67 mm |
| September | 6.2 °C | 24.2 °C | 14.73 mm |
| October | 1.7 °C | 15.8 °C | 37.85 mm |
| November | -1.4 °C | 7.3 °C | 57.91 mm |
| December | -4.2 °C | 2.2 °C | 61.98 mm |
| Annual | 2.5 °C | 15.3 °C | 451.35 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6b : -20.6°C to -17.8°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dsb - Humid Continental Climate - Dry Cool Summer |