Denmark, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 42.3 °F (low) to 61.7 °F (high). Annual precipitation averages 39 Inches. Denmark is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 16.4 °F | 32.8 °F | 1.67 in. |
| February | 19.9 °F | 37.5 °F | 1.87 in. |
| March | 30.1 °F | 50.1 °F | 2.57 in. |
| April | 41.1 °F | 62.7 °F | 3.75 in. |
| May | 53.0 °F | 73.1 °F | 5.28 in. |
| June | 62.6 °F | 82.2 °F | 4.81 in. |
| July | 66.2 °F | 85.6 °F | 4.18 in. |
| August | 64.0 °F | 84.1 °F | 3.8 in. |
| September | 55.5 °F | 78.1 °F | 3.59 in. |
| October | 43.8 °F | 65.4 °F | 3.0 in. |
| November | 32.1 °F | 50.4 °F | 2.53 in. |
| December | 22.3 °F | 38.0 °F | 1.92 in. |
| Annual | 42.3 °F | 61.7 °F | 38.97 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |