Southern Harbour, Newfoundland and Labrador climate data is summarized below. Average annual temperatures range from 2.8 °C (low) to 7.9 °C (high). Annual precipitation averages 1025 Millimeters. Southern Harbour is located in USDA Plant Hardiness Zone . The growing season typically runs from the last frost around Jun. 1 - Jun. 10 through the first frost around Sep.11 - Sep. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -6.13 °C | -0.46 °C | 68 mm |
| February | -6.85 °C | -1.43 °C | 65 mm |
| March | -5.04 °C | -0.24 °C | 61 mm |
| April | -0.99 °C | 3.54 °C | 72 mm |
| May | 3.03 °C | 8.14 °C | 81 mm |
| June | 7.28 °C | 12.55 °C | 72 mm |
| July | 12.17 °C | 17.54 °C | 78 mm |
| August | 13.59 °C | 18.88 °C | 85 mm |
| September | 10.59 °C | 15.88 °C | 108 mm |
| October | 6.43 °C | 10.88 °C | 119 mm |
| November | 2.06 °C | 6.61 °C | 115 mm |
| December | -2.57 °C | 2.3 °C | 101 mm |
| Annual | 2.8 °C | 7.9 °C | 1025 mm |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | Jun. 1 - Jun. 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | |
| Current Drought Conditions | Normal |