Harrold, South Dakota has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 0.8 °C (low) to 14.2 °C (high). Annual precipitation averages 521.7 Millimeters. Harrold 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 Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -14.4 °C | -2.9 °C | 11.18 mm |
| February | -12.2 °C | -0.4 °C | 15.49 mm |
| March | -6.4 °C | 6.6 °C | 22.35 mm |
| April | -0.3 °C | 14.3 °C | 52.83 mm |
| May | 6.5 °C | 20.6 °C | 80.52 mm |
| June | 12.6 °C | 26.1 °C | 92.46 mm |
| July | 15.6 °C | 30.1 °C | 70.1 mm |
| August | 14.5 °C | 29.3 °C | 58.42 mm |
| September | 9.3 °C | 24.8 °C | 47.24 mm |
| October | 1.7 °C | 15.8 °C | 43.69 mm |
| November | -5.7 °C | 6.7 °C | 14.73 mm |
| December | -11.6 °C | -0.7 °C | 12.7 mm |
| Annual | 0.8 °C | 14.2 °C | 521.71 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| 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 | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |