Schleswig, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 3.3 °C (low) to 14.3 °C (high). Annual precipitation averages 824.7 Millimeters. Schleswig is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -12.3 °C | -2.6 °C | 16.76 mm |
| February | -10.1 °C | 0.1 °C | 23.88 mm |
| March | -3.7 °C | 7.5 °C | 45.21 mm |
| April | 2.7 °C | 14.9 °C | 83.57 mm |
| May | 9.6 °C | 21.1 °C | 116.84 mm |
| June | 15.6 °C | 26.6 °C | 120.65 mm |
| July | 17.6 °C | 28.3 °C | 97.79 mm |
| August | 16.1 °C | 27.1 °C | 114.81 mm |
| September | 11.2 °C | 23.8 °C | 82.8 mm |
| October | 4.4 °C | 16.7 °C | 57.91 mm |
| November | -3 °C | 7.7 °C | 33.53 mm |
| December | -8.9 °C | 0.2 °C | 30.99 mm |
| Annual | 3.3 °C | 14.3 °C | 824.74 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |