Long Lake, South Dakota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -0.4 °C (low) to 11.4 °C (high). Annual precipitation averages 543.6 Millimeters. 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 | -16.4 °C | -6.6 °C | 12.45 mm |
| February | -14.1 °C | -4 °C | 14.48 mm |
| March | -8.1 °C | 2.9 °C | 23.62 mm |
| April | -1.1 °C | 11.8 °C | 38.61 mm |
| May | 5.9 °C | 18.8 °C | 80.26 mm |
| June | 12.1 °C | 24.2 °C | 94.74 mm |
| July | 14.6 °C | 27.4 °C | 83.31 mm |
| August | 13.3 °C | 26.9 °C | 64.26 mm |
| September | 8 °C | 22 °C | 56.64 mm |
| October | 0.8 °C | 13.2 °C | 45.21 mm |
| November | -6.9 °C | 3.9 °C | 15.75 mm |
| December | -12.8 °C | -3.6 °C | 14.22 mm |
| Annual | -0.4 °C | 11.4 °C | 543.55 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 | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |