Williamsport, Maryland has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6 °C (low) to 18.5 °C (high). Annual precipitation averages 1058.4 Millimeters. Williamsport 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. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -5.3 °C | 5.1 °C | 74.93 mm |
| February | -4.6 °C | 7.1 °C | 57.66 mm |
| March | -0.8 °C | 11.9 °C | 89.92 mm |
| April | 4.9 °C | 18.7 °C | 89.66 mm |
| May | 10.4 °C | 23.6 °C | 108.2 mm |
| June | 15.2 °C | 28.4 °C | 104.9 mm |
| July | 17.8 °C | 30.9 °C | 91.69 mm |
| August | 16.9 °C | 30 °C | 93.47 mm |
| September | 12.9 °C | 26.2 °C | 102.36 mm |
| October | 6.2 °C | 19.6 °C | 87.63 mm |
| November | 0.9 °C | 13.1 °C | 73.41 mm |
| December | -2.9 °C | 7.1 °C | 84.58 mm |
| Annual | 6 °C | 18.5 °C | 1058.41 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 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 | Severe Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |