Opheim, Montana has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 27.6 °F (low) to 49.9 °F (high). Annual precipitation averages 14 Inches. Opheim is located in USDA Plant Hardiness Zone 4a. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Sep.1 - Sep. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 2.9 °F | 20.5 °F | 0.34 in. |
| February | 5.6 °F | 23.7 °F | 0.31 in. |
| March | 15.4 °F | 35.6 °F | 0.52 in. |
| April | 26.8 °F | 50.7 °F | 0.93 in. |
| May | 37.5 °F | 62.4 °F | 1.97 in. |
| June | 46.8 °F | 70.4 °F | 3.2 in. |
| July | 52.0 °F | 78.7 °F | 2.2 in. |
| August | 50.8 °F | 78.8 °F | 1.32 in. |
| September | 41.4 °F | 67.7 °F | 1.35 in. |
| October | 29.6 °F | 51.7 °F | 0.83 in. |
| November | 16.3 °F | 35.2 °F | 0.61 in. |
| December | 6.2 °F | 23.4 °F | 0.39 in. |
| Annual | 27.6 °F | 49.9 °F | 13.97 in. |
| Average First Frost Date | Sep.1 - Sep. 10 |
| Average Last Frost Date | May 21 - May 31 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 4a : -30°F to -25°F |
| Plant Hardiness Zone - 2012 | Zone 3b : -35°F to -30°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |