Wadena, Iowa has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2.4 °C (low) to 13.8 °C (high). Annual precipitation averages 973.8 Millimeters. Wadena is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -13.1 °C | -3.3 °C | 29.46 mm |
| February | -10.9 °C | -0.9 °C | 30.73 mm |
| March | -4.4 °C | 6.4 °C | 52.32 mm |
| April | 1.9 °C | 14.4 °C | 100.58 mm |
| May | 8.6 °C | 21 °C | 123.19 mm |
| June | 14.3 °C | 26.2 °C | 147.07 mm |
| July | 16.3 °C | 28 °C | 124.97 mm |
| August | 14.9 °C | 26.9 °C | 103.63 mm |
| September | 10.1 °C | 23.4 °C | 93.73 mm |
| October | 3.4 °C | 16.2 °C | 73.91 mm |
| November | -3.2 °C | 7.2 °C | 53.59 mm |
| December | -9.3 °C | -0.1 °C | 40.64 mm |
| Annual | 2.4 °C | 13.8 °C | 973.82 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |