Mount Ayr, Indiana has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 40.7 °F (low) to 60.4 °F (high). Annual precipitation averages 39.7 Inches. Mount Ayr is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 16.8 °F | 32.2 °F | 2.29 in. |
| February | 19.6 °F | 36.7 °F | 1.97 in. |
| March | 28.9 °F | 48.1 °F | 2.54 in. |
| April | 39.1 °F | 61.2 °F | 3.81 in. |
| May | 50.6 °F | 72.1 °F | 4.31 in. |
| June | 60.3 °F | 81.0 °F | 4.99 in. |
| July | 63.1 °F | 83.3 °F | 4.68 in. |
| August | 61.0 °F | 81.9 °F | 3.74 in. |
| September | 53.2 °F | 77.3 °F | 3.19 in. |
| October | 42.0 °F | 64.6 °F | 3.25 in. |
| November | 31.7 °F | 49.6 °F | 2.65 in. |
| December | 22.4 °F | 37.3 °F | 2.23 in. |
| Annual | 40.7 °F | 60.4 °F | 39.65 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |