Mount Sterling, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 5.6 °C (low) to 16.8 °C (high). Annual precipitation averages 966.7 Millimeters. 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 | -8.7 °C | 0.7 °C | 37.08 mm |
| February | -6.8 °C | 3.3 °C | 44.7 mm |
| March | -0.9 °C | 10.4 °C | 57.4 mm |
| April | 5.1 °C | 17.7 °C | 94.23 mm |
| May | 11.4 °C | 23.2 °C | 137.16 mm |
| June | 16.8 °C | 28.4 °C | 122.94 mm |
| July | 18.9 °C | 30.4 °C | 105.92 mm |
| August | 17.7 °C | 29.7 °C | 95.25 mm |
| September | 12.9 °C | 25.9 °C | 94.74 mm |
| October | 6.5 °C | 18.7 °C | 76.71 mm |
| November | 0.1 °C | 10.3 °C | 56.9 mm |
| December | -5.6 °C | 3.4 °C | 43.69 mm |
| Annual | 5.6 °C | 16.8 °C | 966.72 mm |
| 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 : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |