Dundee, Iowa has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2.3 °C (low) to 13.7 °C (high). Annual precipitation averages 985 Millimeters. Dundee 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 | -13.2 °C | -3.4 °C | 30.23 mm |
| February | -11 °C | -1 °C | 32.26 mm |
| March | -4.4 °C | 6.3 °C | 53.85 mm |
| April | 1.9 °C | 14.3 °C | 100.33 mm |
| May | 8.6 °C | 20.8 °C | 122.68 mm |
| June | 14.4 °C | 26.2 °C | 148.59 mm |
| July | 16.2 °C | 27.8 °C | 124.71 mm |
| August | 14.8 °C | 26.8 °C | 103.89 mm |
| September | 9.9 °C | 23.4 °C | 94.23 mm |
| October | 3.2 °C | 16.1 °C | 76.45 mm |
| November | -3.4 °C | 7.2 °C | 56.13 mm |
| December | -9.3 °C | -0.2 °C | 41.66 mm |
| Annual | 2.3 °C | 13.7 °C | 985.01 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 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |