Renfrew, Ontario climate data is summarized below. Average annual temperatures range from 33.9 °F (low) to 52.9 °F (high). Annual precipitation averages 15.3 Inches. Renfrew 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 Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -25.7 °F | -20.4 °F | 0 in. |
| February | -25.6 °F | -20 °F | 0 in. |
| March | -22.2 °F | -16.5 °F | 355.6 in. |
| April | -17.5 °F | -11 °F | 711.2 in. |
| May | -14 °F | -6.7 °F | 965.2 in. |
| June | -11.2 °F | -4.4 °F | 1524 in. |
| July | -9.8 °F | -3.1 °F | 2260.6 in. |
| August | -10.2 °F | -3.8 °F | 1955.8 in. |
| September | -12.7 °F | -6.3 °F | 1041.4 in. |
| October | -15.6 °F | -10.4 °F | 609.6 in. |
| November | -18.9 °F | -14.4 °F | 304.8 in. |
| December | -23.1 °F | -18.9 °F | 177.8 in. |
| Annual | 33.9 °F | 52.9 °F | 15.34 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| 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 |