Fairbank, Iowa has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2.7 °C (low) to 13.8 °C (high). Annual precipitation averages 951 Millimeters. Fairbank 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 | -12.9 °C | -3.3 °C | 28.96 mm |
| February | -10.7 °C | -1 °C | 29.97 mm |
| March | -4.2 °C | 6.4 °C | 49.28 mm |
| April | 2.2 °C | 14.6 °C | 95.25 mm |
| May | 8.9 °C | 21.1 °C | 119.63 mm |
| June | 14.9 °C | 26.4 °C | 145.54 mm |
| July | 16.7 °C | 28 °C | 120.9 mm |
| August | 15.2 °C | 26.9 °C | 108.2 mm |
| September | 10.4 °C | 23.7 °C | 94.74 mm |
| October | 3.6 °C | 16.3 °C | 70.36 mm |
| November | -3.1 °C | 7.2 °C | 48.26 mm |
| December | -9.2 °C | -0.2 °C | 39.88 mm |
| Annual | 2.7 °C | 13.8 °C | 950.97 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 150-180 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 | Dfb - Humid Continental Mild Summer, Wet All Year |