Arnolds Park, Iowa has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2.2 °C (low) to 13.1 °C (high). Annual precipitation averages 763.5 Millimeters. Arnolds Park 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 | -13.9 °C | -4.6 °C | 17.27 mm |
| February | -11.7 °C | -2.2 °C | 19.81 mm |
| March | -5.2 °C | 4.9 °C | 39.12 mm |
| April | 1.7 °C | 13.6 °C | 81.03 mm |
| May | 8.7 °C | 20.4 °C | 110.74 mm |
| June | 14.7 °C | 26.1 °C | 118.11 mm |
| July | 16.8 °C | 28.3 °C | 89.92 mm |
| August | 15.3 °C | 26.8 °C | 92.46 mm |
| September | 10.7 °C | 23.4 °C | 80.52 mm |
| October | 3.3 °C | 15.5 °C | 58.17 mm |
| November | -4 °C | 6.2 °C | 33.27 mm |
| December | -10.5 °C | -1.7 °C | 23.11 mm |
| Annual | 2.2 °C | 13.1 °C | 763.53 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 | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |