Arthur, Ontario climate data is summarized below. Average annual temperatures range from 1.8 °C (low) to 11 °C (high). Annual precipitation averages 588 Millimeters. Arthur 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 Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -11.05 °C | -3.81 °C | 0 mm |
| February | -12.47 °C | -4.24 °C | 0 mm |
| March | -6.46 °C | 2.81 °C | 23 mm |
| April | 0.16 °C | 10.5 °C | 42 mm |
| May | 6.68 °C | 17.89 °C | 81 mm |
| June | 11.59 °C | 22.3 °C | 102 mm |
| July | 13.82 °C | 24.7 °C | 98 mm |
| August | 13.39 °C | 24.11 °C | 104 mm |
| September | 9.5 °C | 20 °C | 58 mm |
| October | 4.38 °C | 12.86 °C | 43 mm |
| November | -1.36 °C | 5.92 °C | 23 mm |
| December | -6.72 °C | -0.79 °C | 14 mm |
| Annual | 1.8 °C | 11 °C | 588 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |