South Middleton, Ontario climate data is summarized below. Average annual temperatures range from 3.8 °C (low) to 13.4 °C (high). Annual precipitation averages 505 Millimeters. South Middleton 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 | -8.21 °C | -1.01 °C | 12 mm |
| February | -10.04 °C | -1.62 °C | 2 mm |
| March | -3.82 °C | 5.44 °C | 29 mm |
| April | 2.1 °C | 12.86 °C | 37 mm |
| May | 8.2 °C | 19.63 °C | 53 mm |
| June | 13.55 °C | 24.59 °C | 65 mm |
| July | 15.61 °C | 26.71 °C | 81 mm |
| August | 15 °C | 25.97 °C | 78 mm |
| September | 10.88 °C | 21.83 °C | 72 mm |
| October | 5.88 °C | 15.11 °C | 37 mm |
| November | 0.54 °C | 8.61 °C | 25 mm |
| December | -3.89 °C | 2.24 °C | 14 mm |
| Annual | 3.8 °C | 13.4 °C | 505 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 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Normal |