Iron Bridge, Ontario climate data is summarized below. Average annual temperatures range from 32.7 °F (low) to 50 °F (high). Annual precipitation averages 17 Inches. Iron Bridge is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -26 °F | -20.8 °F | 0 in. |
| February | -26.6 °F | -20.5 °F | 0 in. |
| March | -23 °F | -17 °F | 127 in. |
| April | -18.6 °F | -13.2 °F | 482.6 in. |
| May | -14.6 °F | -8.7 °F | 1168.4 in. |
| June | -11.6 °F | -5.8 °F | 1905 in. |
| July | -10.1 °F | -4.4 °F | 1930.4 in. |
| August | -10.2 °F | -4.6 °F | 1981.2 in. |
| September | -12.7 °F | -7.1 °F | 1625.6 in. |
| October | -15.6 °F | -11 °F | 1041.4 in. |
| November | -18.7 °F | -14.8 °F | 457.2 in. |
| December | -23.3 °F | -19 °F | 254 in. |
| Annual | 32.7 °F | 50 °F | 17 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Normal |