Roberts, Idaho has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 29.4 °F (low) to 56.7 °F (high). Annual precipitation averages 8.4 Inches. 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 | 9.5 °F | 28.2 °F | 0.47 in. |
| February | 13.2 °F | 33.0 °F | 0.32 in. |
| March | 23.0 °F | 46.1 °F | 0.59 in. |
| April | 29.4 °F | 57.1 °F | 0.79 in. |
| May | 37.3 °F | 66.1 °F | 1.58 in. |
| June | 43.7 °F | 74.6 °F | 1.02 in. |
| July | 48.9 °F | 84.7 °F | 0.46 in. |
| August | 47.0 °F | 84.3 °F | 0.55 in. |
| September | 39.2 °F | 74.0 °F | 0.75 in. |
| October | 29.5 °F | 59.3 °F | 0.86 in. |
| November | 20.1 °F | 42.8 °F | 0.42 in. |
| December | 11.4 °F | 29.7 °F | 0.63 in. |
| Annual | 29.4 °F | 56.7 °F | 8.44 in. |
| 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 : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 4b : -25°F to -20°F |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |