Aylmer, Ontario climate data is summarized below. Average annual temperatures range from 4.4 °C (low) to 13.6 °C (high). Annual precipitation averages 490 Millimeters. Aylmer is located in USDA Plant Hardiness Zone 6b. 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 | -7.78 °C | -0.77 °C | 11 mm |
| February | -9.37 °C | -1.42 °C | 2 mm |
| March | -3.16 °C | 5.54 °C | 27 mm |
| April | 2.59 °C | 12.93 °C | 34 mm |
| May | 8.58 °C | 19.76 °C | 52 mm |
| June | 13.84 °C | 24.66 °C | 64 mm |
| July | 16.25 °C | 26.96 °C | 81 mm |
| August | 15.71 °C | 26.27 °C | 78 mm |
| September | 11.68 °C | 22.31 °C | 71 mm |
| October | 6.46 °C | 15.46 °C | 35 mm |
| November | 1.15 °C | 8.82 °C | 23 mm |
| December | -3.36 °C | 2.45 °C | 12 mm |
| Annual | 4.4 °C | 13.6 °C | 490 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 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Normal |