Pomeroy, Washington has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from 39.2 °F (low) to 61.3 °F (high). Annual precipitation averages 17.4 Inches. Pomeroy 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 | 27.4 °F | 40.0 °F | 2.22 in. |
| February | 28.5 °F | 44.1 °F | 1.63 in. |
| March | 32.8 °F | 51.6 °F | 1.96 in. |
| April | 37.4 °F | 59.1 °F | 1.62 in. |
| May | 43.7 °F | 68.0 °F | 1.59 in. |
| June | 48.9 °F | 74.8 °F | 1.28 in. |
| July | 53.7 °F | 86.0 °F | 0.43 in. |
| August | 53.9 °F | 86.6 °F | 0.45 in. |
| September | 46.8 °F | 77.0 °F | 0.58 in. |
| October | 38.3 °F | 62.0 °F | 1.17 in. |
| November | 31.8 °F | 47.5 °F | 2.2 in. |
| December | 26.6 °F | 38.6 °F | 2.22 in. |
| Annual | 39.2 °F | 61.3 °F | 17.35 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 7a : 0°F to 5°F |
| Plant Hardiness Zone - 2012 | Zone 7a : 0°F to 5°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dsb - Humid Continental Climate - Dry Cool Summer |