St. Lewis, Newfoundland and Labrador climate data is summarized below. Average annual temperatures range from -0.7 °C (low) to 3.4 °C (high). Annual precipitation averages 596 Millimeters. St. Lewis is located in USDA Plant Hardiness Zone 3a. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -11.37 °C | -5.55 °C | 16 mm |
| February | -11.46 °C | -5.36 °C | 15 mm |
| March | -8.27 °C | -3.25 °C | 22 mm |
| April | -3.55 °C | -0.16 °C | 28 mm |
| May | 0.01 °C | 3.03 °C | 55 mm |
| June | 4.51 °C | 8.05 °C | 60 mm |
| July | 9.16 °C | 13.03 °C | 72 mm |
| August | 10.59 °C | 14.29 °C | 58 mm |
| September | 7.48 °C | 11.03 °C | 71 mm |
| October | 3.36 °C | 6.24 °C | 87 mm |
| November | -1.62 °C | 1.78 °C | 69 mm |
| December | -7.19 °C | -2.72 °C | 43 mm |
| Annual | -0.7 °C | 3.4 °C | 596 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 21 - May 31 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 3a : -40°C to -37.2°C |
| Current Drought Conditions | Normal |