Richland, Oregon has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from 2.9 °C (low) to 18.1 °C (high). Annual precipitation averages 325.9 Millimeters. Richland is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Sep.11 - Sep. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -5.4 °C | 3 °C | 42.93 mm |
| February | -3.7 °C | 7.1 °C | 25.65 mm |
| March | -0.7 °C | 12.8 °C | 26.16 mm |
| April | 1.9 °C | 17.4 °C | 34.54 mm |
| May | 6.1 °C | 23.1 °C | 34.54 mm |
| June | 9.7 °C | 27.6 °C | 31.24 mm |
| July | 13.1 °C | 33.6 °C | 8.89 mm |
| August | 12.1 °C | 33.3 °C | 9.14 mm |
| September | 7.3 °C | 27.7 °C | 12.45 mm |
| October | 2.1 °C | 18.8 °C | 22.86 mm |
| November | -2.4 °C | 9.3 °C | 30.99 mm |
| December | -4.9 °C | 3.6 °C | 46.48 mm |
| Annual | 2.9 °C | 18.1 °C | 325.87 mm |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | Over 180 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 | Severe Drought |
| Köppen Climate Classification | Dsb - Humid Continental Climate - Dry Cool Summer |