Seeley Lake, Montana has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 27.1 °F (low) to 55.5 °F (high). Annual precipitation averages 18.8 Inches. Seeley Lake is located in USDA Plant Hardiness Zone 4b. The growing season typically runs from the last frost around Jun. 1 - Jun. 10 through the first frost around Aug. 21 - Aug. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 11.9 °F | 32.2 °F | 2.22 in. |
| February | 13.0 °F | 37.0 °F | 1.9 in. |
| March | 19.7 °F | 45.7 °F | 1.47 in. |
| April | 26.7 °F | 53.4 °F | 1.26 in. |
| May | 33.4 °F | 63.6 °F | 1.48 in. |
| June | 39.8 °F | 71.1 °F | 1.9 in. |
| July | 43.5 °F | 82.6 °F | 0.87 in. |
| August | 42.0 °F | 82.5 °F | 0.83 in. |
| September | 35.7 °F | 71.6 °F | 1.03 in. |
| October | 27.6 °F | 55.5 °F | 1.59 in. |
| November | 19.9 °F | 40.1 °F | 1.95 in. |
| December | 12.2 °F | 31.2 °F | 2.31 in. |
| Annual | 27.1 °F | 55.5 °F | 18.81 in. |
| Average First Frost Date | Aug. 21 - Aug. 31 |
| Average Last Frost Date | Jun. 1 - Jun. 10 |
| 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 | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |