St. Joseph's, Newfoundland and Labrador climate data is summarized below. Average annual temperatures range from 2.3 °C (low) to 8.7 °C (high). Annual precipitation averages 1175 Millimeters. St. Joseph's 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. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -6.23 °C | -0.1 °C | 82 mm |
| February | -7.21 °C | -1.16 °C | 83 mm |
| March | -5.44 °C | 0.08 °C | 80 mm |
| April | -1.63 °C | 4.64 °C | 95 mm |
| May | 2.54 °C | 9.8 °C | 90 mm |
| June | 6.59 °C | 14.25 °C | 81 mm |
| July | 11.68 °C | 19.23 °C | 90 mm |
| August | 12.88 °C | 20.07 °C | 86 mm |
| September | 9.63 °C | 16.82 °C | 109 mm |
| October | 5.82 °C | 11.47 °C | 132 mm |
| November | 1.63 °C | 6.96 °C | 130 mm |
| December | -2.74 °C | 2.57 °C | 117 mm |
| Annual | 2.3 °C | 8.7 °C | 1175 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| 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 |