Cosby, Missouri has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 42.3 °F (low) to 63.5 °F (high). Annual precipitation averages 36.6 Inches. Cosby 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 | 16.6 °F | 35.7 °F | 0.87 in. |
| February | 20.5 °F | 40.9 °F | 1.13 in. |
| March | 30.9 °F | 53.3 °F | 2.37 in. |
| April | 41.2 °F | 64.0 °F | 3.7 in. |
| May | 52.8 °F | 74.0 °F | 5.03 in. |
| June | 62.5 °F | 83.3 °F | 5.15 in. |
| July | 66.6 °F | 87.1 °F | 4.62 in. |
| August | 64.4 °F | 85.8 °F | 3.67 in. |
| September | 55.5 °F | 78.8 °F | 3.64 in. |
| October | 43.3 °F | 66.3 °F | 3.06 in. |
| November | 31.7 °F | 52.9 °F | 1.82 in. |
| December | 21.5 °F | 40.0 °F | 1.54 in. |
| Annual | 42.3 °F | 63.5 °F | 36.6 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 |