Grenville, Quebec climate data is summarized below. Average annual temperatures range from 34.3 °F (low) to 53.1 °F (high). Annual precipitation averages 19.3 Inches. Grenville is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -26 °F | -20.6 °F | 0 in. |
| February | -25.8 °F | -20.2 °F | 0 in. |
| March | -22.2 °F | -16.6 °F | 330.2 in. |
| April | -17.4 °F | -11.3 °F | 990.6 in. |
| May | -13.6 °F | -6.8 °F | 1219.2 in. |
| June | -10.7 °F | -4.3 °F | 2057.4 in. |
| July | -9.4 °F | -2.9 °F | 2667 in. |
| August | -9.8 °F | -3.4 °F | 2133.6 in. |
| September | -12.5 °F | -5.9 °F | 1295.4 in. |
| October | -15.5 °F | -10.1 °F | 1193.8 in. |
| November | -19 °F | -14.3 °F | 508 in. |
| December | -23.2 °F | -18.9 °F | 76.2 in. |
| Annual | 34.3 °F | 53.1 °F | 19.34 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Normal |