Cobourg, Ontario climate data is summarized below. Average annual temperatures range from 4 °C (low) to 11.4 °C (high). Annual precipitation averages 625 Millimeters. Cobourg is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -8.53 °C | -1.2 °C | 12 mm |
| February | -9.52 °C | -1.65 °C | 8 mm |
| March | -3.79 °C | 3.59 °C | 45 mm |
| April | 2.18 °C | 9.44 °C | 69 mm |
| May | 7.46 °C | 15.27 °C | 67 mm |
| June | 12.9 °C | 20.32 °C | 73 mm |
| July | 15.96 °C | 23.65 °C | 81 mm |
| August | 15.91 °C | 23.68 °C | 82 mm |
| September | 11.88 °C | 20.11 °C | 48 mm |
| October | 6.72 °C | 13.8 °C | 56 mm |
| November | 0.89 °C | 7.65 °C | 46 mm |
| December | -4.64 °C | 1.47 °C | 38 mm |
| Annual | 4 °C | 11.4 °C | 625 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Normal |