Sylvanite, Montana has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 31.3 °F (low) to 56.1 °F (high). Annual precipitation averages 33.4 Inches. Sylvanite is located in USDA Plant Hardiness Zone 6a. 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 | 18.1 °F | 31.5 °F | 3.93 in. |
| February | 18.6 °F | 37.6 °F | 2.52 in. |
| March | 24.0 °F | 46.3 °F | 3.23 in. |
| April | 29.2 °F | 55.7 °F | 2.3 in. |
| May | 36.6 °F | 66.7 °F | 2.75 in. |
| June | 42.9 °F | 72.7 °F | 2.78 in. |
| July | 47.0 °F | 83.0 °F | 1.04 in. |
| August | 45.8 °F | 83.3 °F | 0.95 in. |
| September | 38.6 °F | 71.9 °F | 1.61 in. |
| October | 30.9 °F | 54.8 °F | 3.87 in. |
| November | 24.7 °F | 38.8 °F | 4.23 in. |
| December | 18.8 °F | 30.4 °F | 4.16 in. |
| Annual | 31.3 °F | 56.1 °F | 33.37 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 6a : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |