Port Stanley, Ontario climate data is summarized below. Average annual temperatures range from 5.4 °C (low) to 12.6 °C (high). Annual precipitation averages 558 Millimeters. 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 | -6.82 °C | -0.46 °C | 14 mm |
| February | -8.57 °C | -1.29 °C | 6 mm |
| March | -2.68 °C | 4.55 °C | 37 mm |
| April | 2.88 °C | 10.46 °C | 44 mm |
| May | 8.71 °C | 16.92 °C | 61 mm |
| June | 14.41 °C | 22.31 °C | 72 mm |
| July | 17.33 °C | 25.12 °C | 98 mm |
| August | 17.11 °C | 24.93 °C | 78 mm |
| September | 13.51 °C | 21.45 °C | 60 mm |
| October | 8.41 °C | 15.39 °C | 43 mm |
| November | 2.82 °C | 8.93 °C | 27 mm |
| December | -2.14 °C | 2.88 °C | 18 mm |
| Annual | 5.4 °C | 12.6 °C | 558 mm |
| 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 : -20.6°C to -17.8°C |
| Current Drought Conditions | Normal |