Clarion, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 36.3 °F (low) to 56.6 °F (high). Annual precipitation averages 35.2 Inches. Clarion is located in USDA Plant Hardiness Zone 5a. 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 | 8.0 °F | 25.2 °F | 0.8 in. |
| February | 12.0 °F | 29.7 °F | 0.95 in. |
| March | 24.1 °F | 42.5 °F | 2.01 in. |
| April | 35.2 °F | 57.8 °F | 3.88 in. |
| May | 48.1 °F | 69.8 °F | 5.08 in. |
| June | 58.9 °F | 80.1 °F | 5.61 in. |
| July | 62.1 °F | 82.5 °F | 4.39 in. |
| August | 59.1 °F | 80.4 °F | 4.12 in. |
| September | 50.0 °F | 74.8 °F | 3.17 in. |
| October | 37.6 °F | 61.2 °F | 2.27 in. |
| November | 25.5 °F | 44.6 °F | 1.7 in. |
| December | 14.4 °F | 30.8 °F | 1.2 in. |
| Annual | 36.3 °F | 56.6 °F | 35.18 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 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 | Dfa - Humid Continental Hot Summers With Year Around Precipitation |