Riverside, Oregon has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 4.6 °C (low) to 18.2 °C (high). Annual precipitation averages 373.9 Millimeters. Riverside is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -2.2 °C | 5.8 °C | 40.64 mm |
| February | -1.4 °C | 8.7 °C | 33.78 mm |
| March | 1 °C | 13.4 °C | 38.86 mm |
| April | 3.4 °C | 17.2 °C | 38.1 mm |
| May | 7.1 °C | 22.1 °C | 43.43 mm |
| June | 10.4 °C | 26.2 °C | 30.73 mm |
| July | 13.4 °C | 32.2 °C | 8.64 mm |
| August | 12.8 °C | 31.6 °C | 11.43 mm |
| September | 8.6 °C | 26.3 °C | 13.72 mm |
| October | 3.8 °C | 18.5 °C | 27.94 mm |
| November | 0.2 °C | 10.3 °C | 42.93 mm |
| December | -2.3 °C | 5.6 °C | 43.69 mm |
| Annual | 4.6 °C | 18.2 °C | 373.89 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 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 | Extreme Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |