Riverside, Idaho has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 0.4 °C (low) to 14.9 °C (high). Annual precipitation averages 274.6 Millimeters. Riverside is located in USDA Plant Hardiness Zone 5b. 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 | -9.3 °C | -0.2 °C | 23.11 mm |
| February | -7.7 °C | 2.6 °C | 16.51 mm |
| March | -3 °C | 9.2 °C | 25.91 mm |
| April | -0.2 °C | 14.3 °C | 28.45 mm |
| May | 4.1 °C | 19.6 °C | 41.66 mm |
| June | 7.7 °C | 24.6 °C | 22.86 mm |
| July | 10.8 °C | 30.4 °C | 10.67 mm |
| August | 9.9 °C | 30.1 °C | 14.73 mm |
| September | 5.8 °C | 24.3 °C | 23.62 mm |
| October | 0.4 °C | 16 °C | 26.67 mm |
| November | -4.7 °C | 7.3 °C | 18.29 mm |
| December | -9.1 °C | 0.4 °C | 22.1 mm |
| Annual | 0.4 °C | 14.9 °C | 274.58 mm |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |