White Sulphur Springs, Montana has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 28.4 °F (low) to 55 °F (high). Annual precipitation averages 14 Inches. White Sulphur Springs 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 Aug. 21 - Aug. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 13.5 °F | 33.7 °F | 0.82 in. |
| February | 13.4 °F | 35.8 °F | 0.4 in. |
| March | 19.9 °F | 44.1 °F | 0.74 in. |
| April | 26.3 °F | 52.0 °F | 1.32 in. |
| May | 34.4 °F | 61.3 °F | 2.16 in. |
| June | 41.9 °F | 70.1 °F | 2.53 in. |
| July | 47.0 °F | 81.0 °F | 1.3 in. |
| August | 45.3 °F | 80.6 °F | 1.36 in. |
| September | 38.0 °F | 70.0 °F | 1.05 in. |
| October | 28.8 °F | 55.7 °F | 0.77 in. |
| November | 20.0 °F | 41.8 °F | 0.77 in. |
| December | 12.8 °F | 33.4 °F | 0.73 in. |
| Annual | 28.4 °F | 55 °F | 13.95 in. |
| Average First Frost Date | Aug. 21 - Aug. 31 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 4b : -25°F to -20°F |
| Plant Hardiness Zone - 2012 | Zone 4a : -30°F to -25°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |