Rapelje, Montana has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 31.8 °F (low) to 59.3 °F (high). Annual precipitation averages 15.2 Inches. Rapelje is located in USDA Plant Hardiness Zone 4b. 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 | 15.1 °F | 37.6 °F | 0.45 in. |
| February | 15.5 °F | 39.7 °F | 0.42 in. |
| March | 22.5 °F | 48.6 °F | 0.76 in. |
| April | 29.7 °F | 56.6 °F | 1.72 in. |
| May | 38.2 °F | 65.7 °F | 2.84 in. |
| June | 46.3 °F | 74.8 °F | 2.54 in. |
| July | 52.2 °F | 85.6 °F | 1.53 in. |
| August | 50.5 °F | 85.0 °F | 1.08 in. |
| September | 42.2 °F | 74.4 °F | 1.37 in. |
| October | 32.0 °F | 59.9 °F | 1.35 in. |
| November | 22.2 °F | 46.4 °F | 0.58 in. |
| December | 15.6 °F | 37.4 °F | 0.51 in. |
| Annual | 31.8 °F | 59.3 °F | 15.15 in. |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | May 21 - May 31 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 4b : -25°F to -20°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 |