Thessalon, Ontario climate data is summarized below. Average annual temperatures range from 34.4 °F (low) to 48.4 °F (high). Annual precipitation averages 18.8 Inches. Thessalon is located in USDA Plant Hardiness Zone 5a. 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 | -25.1 °F | -20.5 °F | 0 in. |
| February | -25.8 °F | -20.4 °F | 0 in. |
| March | -22.4 °F | -17.4 °F | 152.4 in. |
| April | -18.3 °F | -14.1 °F | 584.2 in. |
| May | -14.7 °F | -10 °F | 1270 in. |
| June | -11.7 °F | -7.2 °F | 1981.2 in. |
| July | -9.9 °F | -5.5 °F | 2057.4 in. |
| August | -9.6 °F | -5.4 °F | 2184.4 in. |
| September | -11.8 °F | -7.6 °F | 1727.2 in. |
| October | -14.7 °F | -11.1 °F | 1320.8 in. |
| November | -17.9 °F | -14.7 °F | 558.8 in. |
| December | -22.4 °F | -18.6 °F | 304.8 in. |
| Annual | 34.4 °F | 48.4 °F | 18.84 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Normal |