Arthur, Ontario climate data is summarized below. Average annual temperatures range from 35.2 °F (low) to 51.8 °F (high). Annual precipitation averages 23.2 Inches. 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 | -23.9 °F | -19.9 °F | 0 in. |
| February | -24.7 °F | -20.1 °F | 0 in. |
| March | -21.4 °F | -16.2 °F | 584.2 in. |
| April | -17.7 °F | -11.9 °F | 1066.8 in. |
| May | -14.1 °F | -7.8 °F | 2057.4 in. |
| June | -11.3 °F | -5.4 °F | 2590.8 in. |
| July | -10.1 °F | -4.1 °F | 2489.2 in. |
| August | -10.3 °F | -4.4 °F | 2641.6 in. |
| September | -12.5 °F | -6.7 °F | 1473.2 in. |
| October | -15.3 °F | -10.6 °F | 1092.2 in. |
| November | -18.5 °F | -14.5 °F | 584.2 in. |
| December | -21.5 °F | -18.2 °F | 355.6 in. |
| Annual | 35.2 °F | 51.8 °F | 23.15 in. |
| 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 : -15°F to -10°F |
| Current Drought Conditions | Normal |