Arion, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 37.8 °F (low) to 59.3 °F (high). Annual precipitation averages 33 Inches. Arion 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. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 10.7 °F | 29.2 °F | 0.73 in. |
| February | 14.8 °F | 34.1 °F | 0.95 in. |
| March | 25.8 °F | 47.3 °F | 1.8 in. |
| April | 36.5 °F | 60.6 °F | 3.42 in. |
| May | 48.8 °F | 71.2 °F | 4.66 in. |
| June | 59.5 °F | 81.2 °F | 4.89 in. |
| July | 63.4 °F | 84.2 °F | 3.91 in. |
| August | 60.5 °F | 82.1 °F | 4.3 in. |
| September | 51.4 °F | 76.3 °F | 3.23 in. |
| October | 39.1 °F | 63.5 °F | 2.45 in. |
| November | 26.2 °F | 47.4 °F | 1.42 in. |
| December | 16.3 °F | 34.2 °F | 1.2 in. |
| Annual | 37.8 °F | 59.3 °F | 32.96 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |