Klein, Montana has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 33 °F (low) to 60.6 °F (high). Annual precipitation averages 15.6 Inches. Klein is located in USDA Plant Hardiness Zone 4b. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 14.0 °F | 37.1 °F | 0.48 in. |
| February | 15.9 °F | 40.0 °F | 0.48 in. |
| March | 23.3 °F | 49.7 °F | 0.83 in. |
| April | 31.2 °F | 58.7 °F | 1.82 in. |
| May | 40.6 °F | 68.0 °F | 2.75 in. |
| June | 49.0 °F | 77.2 °F | 2.99 in. |
| July | 55.1 °F | 88.4 °F | 1.76 in. |
| August | 53.2 °F | 86.6 °F | 0.99 in. |
| September | 43.6 °F | 76.0 °F | 1.21 in. |
| October | 33.1 °F | 61.3 °F | 1.32 in. |
| November | 22.6 °F | 47.1 °F | 0.54 in. |
| December | 14.9 °F | 37.4 °F | 0.46 in. |
| Annual | 33 °F | 60.6 °F | 15.63 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 11 - May 20 |
| 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 | Severe Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |