Maryville, Missouri has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 5.1 °C (low) to 16.7 °C (high). Annual precipitation averages 960.4 Millimeters. Maryville 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 | -9.9 °C | 0.7 °C | 20.83 mm |
| February | -6.8 °C | 4 °C | 30.48 mm |
| March | -1.7 °C | 10.6 °C | 56.39 mm |
| April | 4.3 °C | 17 °C | 97.28 mm |
| May | 10.8 °C | 22.6 °C | 136.65 mm |
| June | 16.3 °C | 27.6 °C | 126.24 mm |
| July | 19 °C | 30.3 °C | 133.35 mm |
| August | 17.8 °C | 29.5 °C | 108.46 mm |
| September | 12.6 °C | 25.7 °C | 90.42 mm |
| October | 5.7 °C | 18.9 °C | 76.45 mm |
| November | -0.8 °C | 10.4 °C | 46.48 mm |
| December | -6.2 °C | 3.4 °C | 37.34 mm |
| Annual | 5.1 °C | 16.7 °C | 960.37 mm |
| 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 : -26.1°C to -23.3°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 |