Durham, Ontario climate data is summarized below. Average annual temperatures range from 2 °C (low) to 11.4 °C (high). Annual precipitation averages 340 Millimeters. Durham is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -10.38 °C | -3.25 °C | 0 mm |
| February | -11.95 °C | -3.79 °C | 0 mm |
| March | -6.23 °C | 3.1 °C | 19 mm |
| April | 0.33 °C | 10.95 °C | 21 mm |
| May | 6.46 °C | 18.19 °C | 43 mm |
| June | 11.46 °C | 22.66 °C | 52 mm |
| July | 13.59 °C | 24.94 °C | 58 mm |
| August | 13.32 °C | 24.27 °C | 70 mm |
| September | 9.6 °C | 20.07 °C | 41 mm |
| October | 4.79 °C | 13.2 °C | 23 mm |
| November | -0.92 °C | 6.39 °C | 10 mm |
| December | -6.25 °C | -0.35 °C | 3 mm |
| Annual | 2 °C | 11.4 °C | 340 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |