Arnolds Park, Iowa has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 35.9 °F (low) to 55.5 °F (high). Annual precipitation averages 30.1 Inches. 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 | 7.0 °F | 23.8 °F | 0.68 in. |
| February | 10.9 °F | 28.1 °F | 0.78 in. |
| March | 22.7 °F | 40.8 °F | 1.54 in. |
| April | 35.0 °F | 56.5 °F | 3.19 in. |
| May | 47.6 °F | 68.8 °F | 4.36 in. |
| June | 58.5 °F | 78.9 °F | 4.65 in. |
| July | 62.3 °F | 83.0 °F | 3.54 in. |
| August | 59.6 °F | 80.2 °F | 3.64 in. |
| September | 51.2 °F | 74.2 °F | 3.17 in. |
| October | 37.9 °F | 59.9 °F | 2.29 in. |
| November | 24.8 °F | 43.2 °F | 1.31 in. |
| December | 13.1 °F | 28.9 °F | 0.91 in. |
| Annual | 35.9 °F | 55.5 °F | 30.06 in. |
| 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 : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |