Potosi, Missouri has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6.9 °C (low) to 18.9 °C (high). Annual precipitation averages 1158 Millimeters. Potosi is located in USDA Plant Hardiness Zone 6b. 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 | -5.6 °C | 5.2 °C | 68.58 mm |
| February | -3.8 °C | 8.2 °C | 70.1 mm |
| March | 0.7 °C | 13.4 °C | 102.87 mm |
| April | 6.5 °C | 19.7 °C | 130.3 mm |
| May | 11.9 °C | 24.2 °C | 141.73 mm |
| June | 16.7 °C | 28.4 °C | 108.46 mm |
| July | 18.9 °C | 30.7 °C | 101.09 mm |
| August | 18.1 °C | 30.3 °C | 92.46 mm |
| September | 13.5 °C | 26.4 °C | 89.92 mm |
| October | 7.2 °C | 20.4 °C | 84.07 mm |
| November | 1.3 °C | 13.2 °C | 93.22 mm |
| December | -3.2 °C | 7.2 °C | 75.18 mm |
| Annual | 6.9 °C | 18.9 °C | 1157.98 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 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 |