Port Kirwan, Newfoundland and Labrador climate data is summarized below. Average annual temperatures range from 37.6 °F (low) to 46.8 °F (high). Annual precipitation averages 43.8 Inches. Port Kirwan 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 | -20.5 °F | -17.5 °F | 2133.6 in. |
| February | -21 °F | -18.1 °F | 2133.6 in. |
| March | -20.2 °F | -17.7 °F | 1955.8 in. |
| April | -18.3 °F | -15.7 °F | 2286 in. |
| May | -16.2 °F | -13.3 °F | 2133.6 in. |
| June | -14 °F | -10.9 °F | 1981.2 in. |
| July | -11.2 °F | -8 °F | 2133.6 in. |
| August | -10.3 °F | -7.3 °F | 1752.6 in. |
| September | -11.9 °F | -8.8 °F | 2387.6 in. |
| October | -14 °F | -11.4 °F | 3098.8 in. |
| November | -16.3 °F | -13.8 °F | 3149.6 in. |
| December | -18.7 °F | -16.1 °F | 3124.2 in. |
| Annual | 37.6 °F | 46.8 °F | 43.82 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 |