Rockville, Missouri has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 7.5 °C (low) to 19.5 °C (high). Annual precipitation averages 1128.5 Millimeters. Rockville is located in USDA Plant Hardiness Zone 6b. 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 | -5.8 °C | 5.4 °C | 44.45 mm |
| February | -3.8 °C | 8.2 °C | 51.31 mm |
| March | 1.4 °C | 13.9 °C | 77.47 mm |
| April | 6.8 °C | 19.7 °C | 119.38 mm |
| May | 12.8 °C | 24.4 °C | 154.18 mm |
| June | 18.2 °C | 29.4 °C | 133.35 mm |
| July | 20.4 °C | 32.1 °C | 113.03 mm |
| August | 19.2 °C | 31.6 °C | 98.55 mm |
| September | 14.3 °C | 27.4 °C | 110.49 mm |
| October | 7.6 °C | 21.2 °C | 87.12 mm |
| November | 1.7 °C | 13.7 °C | 78.99 mm |
| December | -3.3 °C | 7.4 °C | 60.2 mm |
| Annual | 7.5 °C | 19.5 °C | 1128.52 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6b : -20.6°C to -17.8°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |