Seaforth, Ontario climate data is summarized below. Average annual temperatures range from 37.6 °F (low) to 54.8 °F (high). Annual precipitation averages 13.5 Inches. Seaforth is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -22.8 °F | -19 °F | 0 in. |
| February | -23.9 °F | -19.3 °F | 0 in. |
| March | -20.7 °F | -15.4 °F | 533.4 in. |
| April | -16.9 °F | -10.9 °F | 533.4 in. |
| May | -13.3 °F | -6.8 °F | 1117.6 in. |
| June | -10.6 °F | -4.4 °F | 1524 in. |
| July | -9.5 °F | -3.2 °F | 1879.6 in. |
| August | -9.8 °F | -3.6 °F | 1295.4 in. |
| September | -12 °F | -5.8 °F | 889 in. |
| October | -14.7 °F | -9.8 °F | 508 in. |
| November | -17.8 °F | -13.7 °F | 304.8 in. |
| December | -20.6 °F | -17.3 °F | 127 in. |
| Annual | 37.6 °F | 54.8 °F | 13.51 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Normal |