Okreek, 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 15.8 °C (high). Annual precipitation averages 549.1 Millimeters. Okreek is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -11.1 °C | 1.2 °C | 11.43 mm |
| February | -9.6 °C | 3.2 °C | 15.75 mm |
| March | -4.8 °C | 9.1 °C | 28.7 mm |
| April | 0.6 °C | 14.4 °C | 63.25 mm |
| May | 6.8 °C | 20.4 °C | 88.65 mm |
| June | 12.9 °C | 26.4 °C | 95.5 mm |
| July | 16.2 °C | 30.9 °C | 68.07 mm |
| August | 15 °C | 30.2 °C | 54.61 mm |
| September | 9.7 °C | 25.4 °C | 48.51 mm |
| October | 2.2 °C | 16.8 °C | 43.43 mm |
| November | -4.4 °C | 8.9 °C | 17.78 mm |
| December | -9.5 °C | 2.4 °C | 13.46 mm |
| Annual | 2 °C | 15.8 °C | 549.14 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 11 - May 20 |
| 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 |