South Williamsport, Pennsylvania has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.8 °C (low) to 16.4 °C (high). Annual precipitation averages 1108.2 Millimeters. South Williamsport is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -7.1 °C | 1.9 °C | 78.49 mm |
| February | -6.4 °C | 3.7 °C | 59.94 mm |
| March | -2.3 °C | 9 °C | 82.3 mm |
| April | 3.4 °C | 16.5 °C | 91.19 mm |
| May | 9.2 °C | 22.6 °C | 103.38 mm |
| June | 14.2 °C | 27.1 °C | 101.6 mm |
| July | 16.6 °C | 29.5 °C | 111.76 mm |
| August | 15.8 °C | 28.4 °C | 102.11 mm |
| September | 11.7 °C | 24.6 °C | 118.11 mm |
| October | 5.5 °C | 17.7 °C | 100.84 mm |
| November | 0.3 °C | 10.7 °C | 73.15 mm |
| December | -3.7 °C | 4.5 °C | 85.34 mm |
| Annual | 4.8 °C | 16.4 °C | 1108.21 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6b : -20.6°C to -17.8°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |