Southampton, Ontario climate data is summarized below. Average annual temperatures range from 40 °F (low) to 50.5 °F (high). Annual precipitation averages 27.1 Inches. Southampton 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 | -21.7 °F | -18.5 °F | 0 in. |
| February | -22.9 °F | -19.2 °F | 0 in. |
| March | -20.1 °F | -16.5 °F | 914.4 in. |
| April | -17 °F | -13.5 °F | 1879.6 in. |
| May | -14.3 °F | -10.7 °F | 2209.8 in. |
| June | -11.4 °F | -8.1 °F | 2159 in. |
| July | -8.9 °F | -5.7 °F | 1371.6 in. |
| August | -8.5 °F | -5.3 °F | 1803.4 in. |
| September | -10.4 °F | -7 °F | 2133.6 in. |
| October | -13.1 °F | -10.1 °F | 2717.8 in. |
| November | -16.3 °F | -13.5 °F | 1524 in. |
| December | -19.3 °F | -16.7 °F | 762 in. |
| Annual | 40 °F | 50.5 °F | 27.1 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Normal |