Long Lake, South Dakota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 31.3 °F (low) to 52.6 °F (high). Annual precipitation averages 21.4 Inches. Long Lake 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 | 2.4 °F | 20.2 °F | 0.49 in. |
| February | 6.6 °F | 24.8 °F | 0.57 in. |
| March | 17.4 °F | 37.2 °F | 0.93 in. |
| April | 30.0 °F | 53.3 °F | 1.52 in. |
| May | 42.7 °F | 65.9 °F | 3.16 in. |
| June | 53.7 °F | 75.5 °F | 3.73 in. |
| July | 58.3 °F | 81.4 °F | 3.28 in. |
| August | 56.0 °F | 80.4 °F | 2.53 in. |
| September | 46.4 °F | 71.6 °F | 2.23 in. |
| October | 33.4 °F | 55.7 °F | 1.78 in. |
| November | 19.6 °F | 39.1 °F | 0.62 in. |
| December | 8.9 °F | 25.6 °F | 0.56 in. |
| Annual | 31.3 °F | 52.6 °F | 21.4 in. |
| 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 : -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 |