Longlac, Ontario climate data is summarized below. Average annual temperatures range from -4.3 °C (low) to 6.6 °C (high). Annual precipitation averages 598 Millimeters. Longlac is located in USDA Plant Hardiness Zone 2b. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Sep.11 - Sep. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -23.02 °C | -11.7 °C | 0 mm |
| February | -23.71 °C | -10.09 °C | 0 mm |
| March | -15.53 °C | -1.67 °C | 0 mm |
| April | -6.21 °C | 5.91 °C | 11 mm |
| May | 2.43 °C | 14.64 °C | 94 mm |
| June | 8.78 °C | 20.64 °C | 119 mm |
| July | 12.04 °C | 22.87 °C | 117 mm |
| August | 11.31 °C | 22.23 °C | 93 mm |
| September | 6.26 °C | 16.61 °C | 94 mm |
| October | 0.88 °C | 8.55 °C | 67 mm |
| November | -6.99 °C | 0.42 °C | 3 mm |
| December | -18.42 °C | -9.05 °C | 0 mm |
| Annual | -4.3 °C | 6.6 °C | 598 mm |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | May 21 - May 31 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 2b : -42.8°C to -40°C |
| Current Drought Conditions | Normal |