Dundas, Ontario climate data is summarized below. Average annual temperatures range from 4.5 °C (low) to 13.9 °C (high). Annual precipitation averages 964 Millimeters. Dundas is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -7.63 °C | -0.48 °C | 30 mm |
| February | -9.04 °C | -0.8 °C | 36 mm |
| March | -3.25 °C | 5.86 °C | 84 mm |
| April | 2.58 °C | 12.85 °C | 100 mm |
| May | 8.61 °C | 19.95 °C | 100 mm |
| June | 14.09 °C | 24.99 °C | 100 mm |
| July | 16.67 °C | 27.91 °C | 104 mm |
| August | 16.18 °C | 27.03 °C | 96 mm |
| September | 11.98 °C | 22.64 °C | 86 mm |
| October | 6.5 °C | 15.58 °C | 86 mm |
| November | 0.88 °C | 8.8 °C | 71 mm |
| December | -3.77 °C | 2.44 °C | 71 mm |
| Annual | 4.5 °C | 13.9 °C | 964 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Normal |