Williamsburg, Pennsylvania has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 40.6 °F (low) to 61.3 °F (high). Annual precipitation averages 41.6 Inches. Williamsburg is located in USDA Plant Hardiness Zone 7a. 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 | 20.1 °F | 36.5 °F | 2.81 in. |
| February | 20.9 °F | 39.6 °F | 2.37 in. |
| March | 27.7 °F | 48.2 °F | 3.16 in. |
| April | 38.0 °F | 61.6 °F | 3.41 in. |
| May | 48.2 °F | 71.8 °F | 4.07 in. |
| June | 57.5 °F | 79.6 °F | 4.16 in. |
| July | 61.7 °F | 84.1 °F | 3.69 in. |
| August | 60.2 °F | 82.7 °F | 4.11 in. |
| September | 53.3 °F | 75.7 °F | 4.13 in. |
| October | 41.8 °F | 63.8 °F | 3.54 in. |
| November | 32.5 °F | 51.6 °F | 2.95 in. |
| December | 25.3 °F | 40.6 °F | 3.15 in. |
| Annual | 40.6 °F | 61.3 °F | 41.55 in. |
| 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 7a : 0°F to 5°F |
| Plant Hardiness Zone - 2012 | Zone 6b : -5°F to 0°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |