Hanmer, Ontario climate data is summarized below. Average annual temperatures range from 29.7 °F (low) to 49.5 °F (high). Annual precipitation averages 24.4 Inches. 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 | -27.2 °F | -21.7 °F | 0 in. |
| February | -27.4 °F | -21.2 °F | 0 in. |
| March | -23.4 °F | -17 °F | 254 in. |
| April | -19 °F | -12.6 °F | 1397 in. |
| May | -15.1 °F | -7.7 °F | 1803.4 in. |
| June | -12.1 °F | -5.2 °F | 1955.8 in. |
| July | -11 °F | -4 °F | 2057.4 in. |
| August | -11.3 °F | -4.7 °F | 2438.4 in. |
| September | -13.9 °F | -7.3 °F | 2082.8 in. |
| October | -16.9 °F | -11.6 °F | 2616.2 in. |
| November | -20.2 °F | -15.6 °F | 1117.6 in. |
| December | -24.5 °F | -19.9 °F | 0 in. |
| Annual | 29.7 °F | 49.5 °F | 24.38 in. |
| 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 : -25°F to -20°F |
| Current Drought Conditions | Normal |