Hanmer, Ontario climate data is summarized below. Average annual temperatures range from -1.3 °C (low) to 9.7 °C (high). Annual precipitation averages 619 Millimeters. Hanmer is located in USDA Plant Hardiness Zone 4b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -16.88 °C | -7.03 °C | 0 mm |
| February | -17.33 °C | -6.23 °C | 0 mm |
| March | -10.18 °C | 1.37 °C | 10 mm |
| April | -2.25 °C | 9.26 °C | 55 mm |
| May | 4.83 °C | 18.07 °C | 71 mm |
| June | 10.21 °C | 22.72 °C | 77 mm |
| July | 12.16 °C | 24.87 °C | 81 mm |
| August | 11.62 °C | 23.63 °C | 96 mm |
| September | 6.94 °C | 18.89 °C | 82 mm |
| October | 1.67 °C | 11.16 °C | 103 mm |
| November | -4.31 °C | 3.94 °C | 44 mm |
| December | -12.06 °C | -3.9 °C | 0 mm |
| Annual | -1.3 °C | 9.7 °C | 619 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Normal |