Irene, South Dakota has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 2.5 °C (low) to 14.4 °C (high). Annual precipitation averages 697 Millimeters. Irene 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 | -12.8 °C | -2.2 °C | 13.97 mm |
| February | -10.5 °C | 0.6 °C | 18.54 mm |
| March | -4.6 °C | 7.3 °C | 36.32 mm |
| April | 1.8 °C | 14.7 °C | 74.68 mm |
| May | 8.6 °C | 21.1 °C | 99.82 mm |
| June | 14.9 °C | 26.8 °C | 107.7 mm |
| July | 17.1 °C | 29.2 °C | 78.49 mm |
| August | 15.7 °C | 27.9 °C | 81.03 mm |
| September | 10.6 °C | 24.2 °C | 74.68 mm |
| October | 3.1 °C | 16.4 °C | 61.21 mm |
| November | -4.3 °C | 7.4 °C | 29.97 mm |
| December | -10.2 °C | -0.1 °C | 20.57 mm |
| Annual | 2.5 °C | 14.4 °C | 696.98 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 |