Parnell, Missouri has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 40.4 °F (low) to 61.7 °F (high). Annual precipitation averages 38 Inches. Parnell 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 | 13.8 °F | 32.9 °F | 0.88 in. |
| February | 18.3 °F | 38.3 °F | 1.27 in. |
| March | 28.8 °F | 50.8 °F | 2.25 in. |
| April | 39.4 °F | 62.6 °F | 3.85 in. |
| May | 51.3 °F | 72.6 °F | 5.41 in. |
| June | 61.3 °F | 81.6 °F | 5.25 in. |
| July | 65.4 °F | 86.2 °F | 4.88 in. |
| August | 62.9 °F | 84.5 °F | 4.2 in. |
| September | 53.7 °F | 77.4 °F | 3.61 in. |
| October | 41.4 °F | 65.2 °F | 3.01 in. |
| November | 29.6 °F | 50.2 °F | 1.96 in. |
| December | 19.4 °F | 37.7 °F | 1.42 in. |
| Annual | 40.4 °F | 61.7 °F | 37.99 in. |
| 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 : -15°F to -10°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 |