Melstone, Montana has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 0.8 °C (low) to 15.9 °C (high). Annual precipitation averages 385.3 Millimeters. Melstone 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 | -10.8 °C | 1.8 °C | 12.7 mm |
| February | -9.4 °C | 3.8 °C | 12.45 mm |
| March | -4.8 °C | 9.6 °C | 19.81 mm |
| April | 0.1 °C | 15.2 °C | 40.89 mm |
| May | 5.4 °C | 20.2 °C | 64.26 mm |
| June | 10.2 °C | 25.6 °C | 74.68 mm |
| July | 13.7 °C | 31.3 °C | 40.89 mm |
| August | 12.6 °C | 30.9 °C | 28.96 mm |
| September | 7.2 °C | 24.8 °C | 29.72 mm |
| October | 0.9 °C | 16.3 °C | 32.51 mm |
| November | -5.1 °C | 8.3 °C | 14.48 mm |
| December | -9.9 °C | 2.6 °C | 13.97 mm |
| Annual | 0.8 °C | 15.9 °C | 385.32 mm |
| 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 : -31.7°C to -28.9°C |
| Plant Hardiness Zone - 2012 | Zone 4a : -34.4°C to -31.7°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |