Brooklin, Ontario climate data is summarized below. Average annual temperatures range from 38.3 °F (low) to 55.6 °F (high). Annual precipitation averages 37.8 Inches. Brooklin is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -22.8 °F | -18.5 °F | 533.4 in. |
| February | -23.4 °F | -18.7 °F | 431.8 in. |
| March | -20.3 °F | -15.1 °F | 1651 in. |
| April | -16.6 °F | -10.8 °F | 2590.8 in. |
| May | -13.1 °F | -6.8 °F | 2540 in. |
| June | -10.4 °F | -4.2 °F | 3200.4 in. |
| July | -9 °F | -2.7 °F | 2921 in. |
| August | -9.3 °F | -3.2 °F | 2997.2 in. |
| September | -11.8 °F | -5.7 °F | 1930.4 in. |
| October | -14.7 °F | -9.7 °F | 2336.8 in. |
| November | -17.9 °F | -13.3 °F | 1701.8 in. |
| December | -20.7 °F | -17 °F | 1524 in. |
| Annual | 38.3 °F | 55.6 °F | 37.77 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Normal |