Alpena, South Dakota has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 1.6 °C (low) to 14.2 °C (high). Annual precipitation averages 604.5 Millimeters. Alpena is located in USDA Plant Hardiness Zone 4b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -14.2 °C | -3.3 °C | 14.22 mm |
| February | -11.9 °C | -0.2 °C | 17.02 mm |
| March | -5.7 °C | 6.5 °C | 26.42 mm |
| April | 0.8 °C | 14.4 °C | 66.29 mm |
| May | 7.9 °C | 21 °C | 86.36 mm |
| June | 14 °C | 26.6 °C | 98.55 mm |
| July | 16.5 °C | 29.8 °C | 75.69 mm |
| August | 15.2 °C | 28.7 °C | 69.34 mm |
| September | 10.2 °C | 24.3 °C | 61.72 mm |
| October | 2.3 °C | 16.2 °C | 52.32 mm |
| November | -5.1 °C | 6.9 °C | 20.57 mm |
| December | -11.3 °C | -0.7 °C | 16 mm |
| Annual | 1.6 °C | 14.2 °C | 604.5 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 4b : -31.7°C to -28.9°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |