Williamsburg, Ontario climate data is summarized below. Average annual temperatures range from 35.3 °F (low) to 54.5 °F (high). Annual precipitation averages 23.8 Inches. Williamsburg is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -25.1 °F | -19.9 °F | 0 in. |
| February | -25.1 °F | -19.6 °F | 25.4 in. |
| March | -21.6 °F | -15.8 °F | 584.2 in. |
| April | -17.1 °F | -10.8 °F | 1320.8 in. |
| May | -13.5 °F | -6.5 °F | 1651 in. |
| June | -10.6 °F | -4.1 °F | 2184.4 in. |
| July | -9.2 °F | -2.6 °F | 2946.4 in. |
| August | -9.8 °F | -3.1 °F | 2159 in. |
| September | -12.4 °F | -5.6 °F | 1651 in. |
| October | -15.3 °F | -9.8 °F | 1625.6 in. |
| November | -18.7 °F | -13.8 °F | 838.2 in. |
| December | -22.4 °F | -18.3 °F | 330.2 in. |
| Annual | 35.3 °F | 54.5 °F | 23.76 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Normal |