Port Stanley, Ontario climate data is summarized below. Average annual temperatures range from 41.7 °F (low) to 54.7 °F (high). Annual precipitation averages 22 Inches. Port Stanley is located in USDA Plant Hardiness Zone 6b. 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 | -21.6 °F | -18 °F | 355.6 in. |
| February | -22.5 °F | -18.5 °F | 152.4 in. |
| March | -19.3 °F | -15.3 °F | 939.8 in. |
| April | -16.2 °F | -12 °F | 1117.6 in. |
| May | -12.9 °F | -8.4 °F | 1549.4 in. |
| June | -9.8 °F | -5.4 °F | 1828.8 in. |
| July | -8.2 °F | -3.8 °F | 2489.2 in. |
| August | -8.3 °F | -3.9 °F | 1981.2 in. |
| September | -10.3 °F | -5.9 °F | 1524 in. |
| October | -13.1 °F | -9.2 °F | 1092.2 in. |
| November | -16.2 °F | -12.8 °F | 685.8 in. |
| December | -19 °F | -16.2 °F | 457.2 in. |
| Annual | 41.7 °F | 54.7 °F | 21.96 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6b : -5°F to 0°F |
| Current Drought Conditions | Normal |