St. Stephen, New Brunswick climate data is summarized below. Average annual temperatures range from 1.2 °C (low) to 11.9 °C (high). Annual precipitation averages 956 Millimeters. St. Stephen is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -12.61 °C | -2.29 °C | 25 mm |
| February | -11.89 °C | -1.24 °C | 30 mm |
| March | -7.08 °C | 3.85 °C | 70 mm |
| April | -0.16 °C | 10.88 °C | 94 mm |
| May | 5.53 °C | 17.08 °C | 96 mm |
| June | 10.34 °C | 21.69 °C | 84 mm |
| July | 13.99 °C | 25.6 °C | 83 mm |
| August | 13.36 °C | 24.98 °C | 78 mm |
| September | 8.77 °C | 20.55 °C | 74 mm |
| October | 3.63 °C | 13.82 °C | 114 mm |
| November | -1.57 °C | 7.4 °C | 114 mm |
| December | -8.03 °C | 0.79 °C | 94 mm |
| Annual | 1.2 °C | 11.9 °C | 956 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Abnormally Dry |