Loomis, South Dakota has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 2 °C (low) to 14.3 °C (high). Annual precipitation averages 628.7 Millimeters. Loomis is located in USDA Plant Hardiness Zone 5a. 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 | -13.6 °C | -2.8 °C | 14.22 mm |
| February | -11.3 °C | 0.2 °C | 19.56 mm |
| March | -5.4 °C | 6.7 °C | 30.99 mm |
| April | 1.3 °C | 14.3 °C | 74.93 mm |
| May | 8.3 °C | 21 °C | 87.38 mm |
| June | 14.6 °C | 26.6 °C | 96.01 mm |
| July | 16.9 °C | 29.7 °C | 73.91 mm |
| August | 15.6 °C | 28.6 °C | 74.42 mm |
| September | 10.4 °C | 24.4 °C | 64.77 mm |
| October | 2.6 °C | 16.2 °C | 51.56 mm |
| November | -4.8 °C | 7.1 °C | 22.61 mm |
| December | -10.8 °C | -0.4 °C | 18.29 mm |
| Annual | 2 °C | 14.3 °C | 628.65 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 5a : -28.9°C to -26.1°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 |