Mount Sterling, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 42.1 °F (low) to 62.3 °F (high). Annual precipitation averages 38.1 Inches. Mount Sterling is located in USDA Plant Hardiness Zone 6a. 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 | 16.3 °F | 33.3 °F | 1.46 in. |
| February | 19.7 °F | 37.9 °F | 1.76 in. |
| March | 30.3 °F | 50.7 °F | 2.26 in. |
| April | 41.1 °F | 63.9 °F | 3.71 in. |
| May | 52.5 °F | 73.8 °F | 5.4 in. |
| June | 62.2 °F | 83.1 °F | 4.84 in. |
| July | 66.1 °F | 86.8 °F | 4.17 in. |
| August | 63.9 °F | 85.4 °F | 3.75 in. |
| September | 55.3 °F | 78.6 °F | 3.73 in. |
| October | 43.7 °F | 65.6 °F | 3.02 in. |
| November | 32.1 °F | 50.6 °F | 2.24 in. |
| December | 22.0 °F | 38.2 °F | 1.72 in. |
| Annual | 42.1 °F | 62.3 °F | 38.06 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°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 |