South Fork, Missouri has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 7.6 °C (low) to 19.7 °C (high). Annual precipitation averages 1214.6 Millimeters. South Fork is located in USDA Plant Hardiness Zone 7a. 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 | -4.4 °C | 6.7 °C | 76.71 mm |
| February | -2.5 °C | 9.3 °C | 77.22 mm |
| March | 1.7 °C | 14.5 °C | 116.08 mm |
| April | 7.3 °C | 20.4 °C | 136.65 mm |
| May | 12.3 °C | 24.4 °C | 133.6 mm |
| June | 17.2 °C | 28.8 °C | 93.98 mm |
| July | 19.3 °C | 31.4 °C | 99.57 mm |
| August | 18.5 °C | 31.2 °C | 87.63 mm |
| September | 14.2 °C | 27.1 °C | 102.11 mm |
| October | 7.7 °C | 20.9 °C | 93.47 mm |
| November | 2.1 °C | 14 °C | 113.28 mm |
| December | -2.6 °C | 8.2 °C | 84.33 mm |
| Annual | 7.6 °C | 19.7 °C | 1214.63 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |