Glenwood, Washington has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from 1.7 °C (low) to 15.2 °C (high). Annual precipitation averages 797.1 Millimeters. Glenwood is located in USDA Plant Hardiness Zone 7a. 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 | -3.7 °C | 3.7 °C | 136.65 mm |
| February | -3.2 °C | 6.3 °C | 97.03 mm |
| March | -1.3 °C | 10.1 °C | 83.06 mm |
| April | 0.3 °C | 13.8 °C | 41.91 mm |
| May | 3.6 °C | 19.2 °C | 33.27 mm |
| June | 6.2 °C | 22.3 °C | 18.29 mm |
| July | 8.9 °C | 27.8 °C | 5.33 mm |
| August | 8.6 °C | 28.2 °C | 6.35 mm |
| September | 5 °C | 23.6 °C | 19.05 mm |
| October | 1.2 °C | 15.8 °C | 61.47 mm |
| November | -1.6 °C | 7.9 °C | 119.38 mm |
| December | -3.8 °C | 3.1 °C | 175.26 mm |
| Annual | 1.7 °C | 15.2 °C | 797.05 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 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dsb - Humid Continental Climate - Dry Cool Summer |