Wiarton, Ontario climate data is summarized below. Average annual temperatures range from 37.4 °F (low) to 52.2 °F (high). Annual precipitation averages 27.8 Inches. Wiarton is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -22.7 °F | -19 °F | 0 in. |
| February | -23.7 °F | -19.5 °F | 0 in. |
| March | -20.7 °F | -16.2 °F | 812.8 in. |
| April | -17.3 °F | -12.3 °F | 1955.8 in. |
| May | -14.3 °F | -8.6 °F | 2413 in. |
| June | -11.4 °F | -6 °F | 2260.6 in. |
| July | -9.7 °F | -4.5 °F | 1473.2 in. |
| August | -9.7 °F | -4.6 °F | 2032 in. |
| September | -11.8 °F | -6.7 °F | 2108.2 in. |
| October | -14.3 °F | -10.2 °F | 2844.8 in. |
| November | -17.4 °F | -13.7 °F | 1574.8 in. |
| December | -20.3 °F | -17.3 °F | 482.6 in. |
| Annual | 37.4 °F | 52.2 °F | 27.83 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Normal |