Yorktown, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.4 °C (low) to 16.4 °C (high). Annual precipitation averages 887.7 Millimeters. Yorktown is located in USDA Plant Hardiness Zone 5b. 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 | -10.5 °C | 0.3 °C | 21.59 mm |
| February | -8.1 °C | 3.3 °C | 26.67 mm |
| March | -2.1 °C | 10.4 °C | 48.01 mm |
| April | 3.6 °C | 17 °C | 81.03 mm |
| May | 10.4 °C | 22.6 °C | 143.76 mm |
| June | 16.2 °C | 27.6 °C | 136.65 mm |
| July | 18.4 °C | 29.6 °C | 108.97 mm |
| August | 16.9 °C | 28.8 °C | 92.46 mm |
| September | 11.8 °C | 25.5 °C | 77.22 mm |
| October | 5 °C | 18.8 °C | 71.37 mm |
| November | -1.8 °C | 10.1 °C | 49.78 mm |
| December | -7.4 °C | 3.1 °C | 30.23 mm |
| Annual | 4.4 °C | 16.4 °C | 887.74 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 5b : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |