Bethany, Missouri has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 5.2 °C (low) to 16.7 °C (high). Annual precipitation averages 1005.1 Millimeters. Bethany 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 | -9.2 °C | 0.9 °C | 24.38 mm |
| February | -7.1 °C | 3.8 °C | 38.86 mm |
| March | -1.2 °C | 10.7 °C | 58.42 mm |
| April | 4.7 °C | 17.1 °C | 99.31 mm |
| May | 11.1 °C | 22.6 °C | 141.99 mm |
| June | 16.6 °C | 27.8 °C | 140.21 mm |
| July | 18.8 °C | 30.3 °C | 120.65 mm |
| August | 17.6 °C | 29.5 °C | 107.7 mm |
| September | 12.7 °C | 25.4 °C | 103.89 mm |
| October | 5.9 °C | 18.5 °C | 77.22 mm |
| November | -0.7 °C | 10.4 °C | 51.05 mm |
| December | -6.3 °C | 3.6 °C | 41.4 mm |
| Annual | 5.2 °C | 16.7 °C | 1005.08 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 |