Dunlap, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 3.4 °C (low) to 15.7 °C (high). Annual precipitation averages 832.9 Millimeters. Dunlap 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 | -11.7 °C | -1.1 °C | 18.29 mm |
| February | -9.4 °C | 1.7 °C | 23.62 mm |
| March | -3.2 °C | 9.2 °C | 45.21 mm |
| April | 2.8 °C | 16.5 °C | 87.38 mm |
| May | 9.7 °C | 22.4 °C | 119.13 mm |
| June | 15.7 °C | 27.9 °C | 124.46 mm |
| July | 17.8 °C | 29.7 °C | 96.77 mm |
| August | 16.2 °C | 28.5 °C | 106.93 mm |
| September | 11.1 °C | 25.2 °C | 82.8 mm |
| October | 4 °C | 18.1 °C | 61.72 mm |
| November | -3.1 °C | 9.1 °C | 35.81 mm |
| December | -8.7 °C | 1.7 °C | 30.73 mm |
| Annual | 3.4 °C | 15.7 °C | 832.85 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 5b : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |