Harbour Grace, Newfoundland and Labrador climate data is summarized below. Average annual temperatures range from 37.2 °F (low) to 46.3 °F (high). Annual precipitation averages 38.5 Inches. 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 | -20.8 °F | -17.9 °F | 1600.2 in. |
| February | -21.3 °F | -18.4 °F | 1600.2 in. |
| March | -20.4 °F | -17.9 °F | 1498.6 in. |
| April | -18.4 °F | -15.8 °F | 1752.6 in. |
| May | -16.2 °F | -13.3 °F | 2006.6 in. |
| June | -14 °F | -10.9 °F | 1701.8 in. |
| July | -11.2 °F | -7.9 °F | 1955.8 in. |
| August | -10.3 °F | -7.4 °F | 1981.2 in. |
| September | -11.9 °F | -8.9 °F | 2540 in. |
| October | -14.1 °F | -11.6 °F | 2895.6 in. |
| November | -16.5 °F | -14 °F | 2717.8 in. |
| December | -19 °F | -16.4 °F | 2565.4 in. |
| Annual | 37.2 °F | 46.3 °F | 38.47 in. |
| 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 : -15°F to -10°F |
| Current Drought Conditions | Normal |