Brooklin, Ontario climate data is summarized below. Average annual temperatures range from 3.5 °C (low) to 13.1 °C (high). Annual precipitation averages 959 Millimeters. 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 | -9.01 °C | -1.27 °C | 21 mm |
| February | -10.13 °C | -1.64 °C | 17 mm |
| March | -4.45 °C | 4.88 °C | 65 mm |
| April | 2.19 °C | 12.58 °C | 102 mm |
| May | 8.36 °C | 19.73 °C | 100 mm |
| June | 13.35 °C | 24.41 °C | 126 mm |
| July | 15.84 °C | 27.12 °C | 115 mm |
| August | 15.18 °C | 26.18 °C | 118 mm |
| September | 10.73 °C | 21.7 °C | 76 mm |
| October | 5.5 °C | 14.52 °C | 92 mm |
| November | -0.22 °C | 7.99 °C | 67 mm |
| December | -5.18 °C | 1.37 °C | 60 mm |
| Annual | 3.5 °C | 13.1 °C | 959 mm |
| 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 : -23.3°C to -20.6°C |
| Current Drought Conditions | Normal |