Dunnville, Ontario climate data is summarized below. Average annual temperatures range from 4.7 °C (low) to 13.1 °C (high). Annual precipitation averages 917 Millimeters. Dunnville is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -7.58 °C | -0.64 °C | 39 mm |
| February | -9.32 °C | -1.4 °C | 37 mm |
| March | -3.39 °C | 5.16 °C | 83 mm |
| April | 2.28 °C | 11.72 °C | 92 mm |
| May | 8.33 °C | 18.59 °C | 98 mm |
| June | 14.14 °C | 23.42 °C | 79 mm |
| July | 16.99 °C | 25.95 °C | 84 mm |
| August | 16.71 °C | 25.58 °C | 76 mm |
| September | 12.75 °C | 21.7 °C | 82 mm |
| October | 7.42 °C | 15.2 °C | 100 mm |
| November | 1.73 °C | 8.82 °C | 69 mm |
| December | -3.08 °C | 2.81 °C | 78 mm |
| Annual | 4.7 °C | 13.1 °C | 917 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Normal |