Rockwood, Ontario climate data is summarized below. Average annual temperatures range from 2.9 °C (low) to 12.5 °C (high). Annual precipitation averages 865 Millimeters. Rockwood is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -9.73 °C | -2.45 °C | 13 mm |
| February | -11 °C | -2.65 °C | 10 mm |
| March | -5.46 °C | 4.25 °C | 54 mm |
| April | 1.24 °C | 12.04 °C | 85 mm |
| May | 7.66 °C | 19.27 °C | 115 mm |
| June | 12.66 °C | 23.84 °C | 105 mm |
| July | 15.09 °C | 26.52 °C | 118 mm |
| August | 14.45 °C | 25.76 °C | 120 mm |
| September | 10.43 °C | 21.52 °C | 81 mm |
| October | 5.07 °C | 14.23 °C | 73 mm |
| November | -0.66 °C | 7.38 °C | 51 mm |
| December | -5.55 °C | 0.4 °C | 40 mm |
| Annual | 2.9 °C | 12.5 °C | 865 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |