Winchester, Missouri has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 8.4 °C (low) to 19.1 °C (high). Annual precipitation averages 1127.3 Millimeters. Winchester is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -4.7 °C | 4.6 °C | 71.63 mm |
| February | -2.8 °C | 7.6 °C | 62.48 mm |
| March | 2.1 °C | 13.3 °C | 92.2 mm |
| April | 7.9 °C | 19.8 °C | 120.9 mm |
| May | 13.9 °C | 24.8 °C | 136.65 mm |
| June | 18.9 °C | 29.4 °C | 118.11 mm |
| July | 21.1 °C | 31.4 °C | 103.38 mm |
| August | 19.9 °C | 30.8 °C | 89.66 mm |
| September | 15.4 °C | 27.1 °C | 84.58 mm |
| October | 8.8 °C | 20.7 °C | 84.84 mm |
| November | 2.7 °C | 13 °C | 92.46 mm |
| December | -2.1 °C | 7 °C | 70.36 mm |
| Annual | 8.4 °C | 19.1 °C | 1127.25 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |