Maryhill, Washington has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from 44.5 °F (low) to 65.1 °F (high). Annual precipitation averages 10.8 Inches. Maryhill is located in USDA Plant Hardiness Zone 8a. 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 | 32.2 °F | 42.9 °F | 1.9 in. |
| February | 33.1 °F | 48.4 °F | 1.27 in. |
| March | 37.2 °F | 56.9 °F | 0.99 in. |
| April | 42.1 °F | 63.5 °F | 0.61 in. |
| May | 48.8 °F | 72.0 °F | 0.63 in. |
| June | 54.4 °F | 78.4 °F | 0.33 in. |
| July | 60.3 °F | 88.4 °F | 0.15 in. |
| August | 60.2 °F | 89.0 °F | 0.16 in. |
| September | 52.9 °F | 80.5 °F | 0.27 in. |
| October | 43.9 °F | 66.4 °F | 0.76 in. |
| November | 36.8 °F | 51.8 °F | 1.53 in. |
| December | 32.2 °F | 42.6 °F | 2.15 in. |
| Annual | 44.5 °F | 65.1 °F | 10.75 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 8a : 10°F to 15°F |
| Plant Hardiness Zone - 2012 | Zone 7b : 5°F to 10°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dsb - Humid Continental Climate - Dry Cool Summer |