Grand Falls-Windsor, Newfoundland and Labrador climate data is summarized below. Average annual temperatures range from -0.1 °C (low) to 7.8 °C (high). Annual precipitation averages 792 Millimeters. Grand Falls-Windsor is located in USDA Plant Hardiness Zone 4b. The growing season typically runs from the last frost around Jun. 1 - Jun. 10 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -10.65 °C | -3.56 °C | 20 mm |
| February | -11.38 °C | -3.89 °C | 26 mm |
| March | -9.39 °C | -1.96 °C | 21 mm |
| April | -3.49 °C | 3.55 °C | 48 mm |
| May | 1.46 °C | 10.54 °C | 72 mm |
| June | 6.39 °C | 16.09 °C | 77 mm |
| July | 11.43 °C | 21.66 °C | 86 mm |
| August | 11.3 °C | 21.11 °C | 104 mm |
| September | 7.48 °C | 16.39 °C | 102 mm |
| October | 3.26 °C | 9.82 °C | 103 mm |
| November | -1.15 °C | 4.42 °C | 86 mm |
| December | -6.14 °C | -0.58 °C | 47 mm |
| Annual | -0.1 °C | 7.8 °C | 792 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | Jun. 1 - Jun. 10 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Normal |