Southampton, Ontario climate data is summarized below. Average annual temperatures range from 4.4 °C (low) to 10.3 °C (high). Annual precipitation averages 688 Millimeters. 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 | -7.04 °C | -1.28 °C | 0 mm |
| February | -9.22 °C | -2.53 °C | 0 mm |
| March | -4.25 °C | 2.38 °C | 36 mm |
| April | 1.33 °C | 7.73 °C | 74 mm |
| May | 6.32 °C | 12.73 °C | 87 mm |
| June | 11.46 °C | 17.5 °C | 85 mm |
| July | 16.05 °C | 21.69 °C | 54 mm |
| August | 16.75 °C | 22.45 °C | 71 mm |
| September | 13.22 °C | 19.34 °C | 84 mm |
| October | 8.38 °C | 13.75 °C | 107 mm |
| November | 2.75 °C | 7.79 °C | 60 mm |
| December | -2.7 °C | 1.98 °C | 30 mm |
| Annual | 4.4 °C | 10.3 °C | 688 mm |
| 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 : -23.3°C to -20.6°C |
| Current Drought Conditions | Normal |