Haileybury, Ontario climate data is summarized below. Average annual temperatures range from 29.6 °F (low) to 46.8 °F (high). Annual precipitation averages 25.8 Inches. Haileybury is located in USDA Plant Hardiness Zone 3b. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -28 °F | -22.6 °F | 0 in. |
| February | -27.9 °F | -22.3 °F | 0 in. |
| March | -24 °F | -18.3 °F | 152.4 in. |
| April | -19.4 °F | -13.8 °F | 1270 in. |
| May | -15.2 °F | -8.6 °F | 1701.8 in. |
| June | -12.1 °F | -6.1 °F | 1879.6 in. |
| July | -10.6 °F | -4.9 °F | 2616.2 in. |
| August | -10.9 °F | -5.4 °F | 2844.8 in. |
| September | -13.4 °F | -7.9 °F | 2260.6 in. |
| October | -16.4 °F | -12 °F | 2794 in. |
| November | -19.7 °F | -15.9 °F | 1092.2 in. |
| December | -25 °F | -20.6 °F | 0 in. |
| Annual | 29.6 °F | 46.8 °F | 25.75 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 3b : -35°F to -30°F |
| Current Drought Conditions | Normal |