Roberts, Idaho has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from -1.5 °C (low) to 13.7 °C (high). Annual precipitation averages 214.4 Millimeters. Roberts is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Sep.11 - Sep. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -12.5 °C | -2.1 °C | 11.94 mm |
| February | -10.4 °C | 0.6 °C | 8.13 mm |
| March | -5 °C | 7.8 °C | 14.99 mm |
| April | -1.4 °C | 13.9 °C | 20.07 mm |
| May | 2.9 °C | 18.9 °C | 40.13 mm |
| June | 6.5 °C | 23.7 °C | 25.91 mm |
| July | 9.4 °C | 29.3 °C | 11.68 mm |
| August | 8.3 °C | 29.1 °C | 13.97 mm |
| September | 4 °C | 23.3 °C | 19.05 mm |
| October | -1.4 °C | 15.2 °C | 21.84 mm |
| November | -6.6 °C | 6 °C | 10.67 mm |
| December | -11.4 °C | -1.3 °C | 16 mm |
| Annual | -1.5 °C | 13.7 °C | 214.38 mm |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | May 21 - May 31 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |