Redfield, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 3.9 °C (low) to 15.6 °C (high). Annual precipitation averages 899.9 Millimeters. Redfield 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 | -11.3 °C | -1.2 °C | 22.61 mm |
| February | -9 °C | 1.5 °C | 29.72 mm |
| March | -2.9 °C | 8.7 °C | 51.56 mm |
| April | 3.3 °C | 16.2 °C | 93.22 mm |
| May | 10.1 °C | 22.2 °C | 126.24 mm |
| June | 15.8 °C | 27.4 °C | 132.08 mm |
| July | 18 °C | 29.6 °C | 106.17 mm |
| August | 16.4 °C | 28.6 °C | 103.12 mm |
| September | 11.6 °C | 25.2 °C | 87.63 mm |
| October | 4.7 °C | 17.7 °C | 68.07 mm |
| November | -2.1 °C | 9 °C | 45.72 mm |
| December | -8.1 °C | 1.7 °C | 33.78 mm |
| Annual | 3.9 °C | 15.6 °C | 899.92 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 | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |