Port Kirwan, Newfoundland and Labrador climate data is summarized below. Average annual temperatures range from 3.1 °C (low) to 8.2 °C (high). Annual precipitation averages 1113 Millimeters. 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 | -4.91 °C | 0.42 °C | 84 mm |
| February | -5.76 °C | -0.61 °C | 84 mm |
| March | -4.29 °C | 0.23 °C | 77 mm |
| April | -0.96 °C | 3.81 °C | 90 mm |
| May | 2.83 °C | 8.07 °C | 84 mm |
| June | 6.8 °C | 12.31 °C | 78 mm |
| July | 11.88 °C | 17.52 °C | 84 mm |
| August | 13.51 °C | 18.9 °C | 69 mm |
| September | 10.63 °C | 16.24 °C | 94 mm |
| October | 6.78 °C | 11.41 °C | 122 mm |
| November | 2.6 °C | 7.14 °C | 124 mm |
| December | -1.64 °C | 3.05 °C | 123 mm |
| Annual | 3.1 °C | 8.2 °C | 1113 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 |