Harbour Grace, Newfoundland and Labrador climate data is summarized below. Average annual temperatures range from 2.9 °C (low) to 8 °C (high). Annual precipitation averages 977 Millimeters. Harbour Grace is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -5.51 °C | -0.15 °C | 63 mm |
| February | -6.29 °C | -1.19 °C | 63 mm |
| March | -4.63 °C | -0.17 °C | 59 mm |
| April | -1.05 °C | 3.58 °C | 69 mm |
| May | 2.79 °C | 8.05 °C | 79 mm |
| June | 6.84 °C | 12.34 °C | 67 mm |
| July | 11.93 °C | 17.8 °C | 77 mm |
| August | 13.45 °C | 18.77 °C | 78 mm |
| September | 10.52 °C | 15.95 °C | 100 mm |
| October | 6.6 °C | 11.06 °C | 114 mm |
| November | 2.32 °C | 6.77 °C | 107 mm |
| December | -2.13 °C | 2.52 °C | 101 mm |
| Annual | 2.9 °C | 8 °C | 977 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 21 - May 31 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |