Renfrew, Ontario climate data is summarized below. Average annual temperatures range from 1.1 °C (low) to 11.6 °C (high). Annual precipitation averages 390 Millimeters. 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 | -14.22 °C | -4.72 °C | 0 mm |
| February | -14.04 °C | -4.02 °C | 0 mm |
| March | -8 °C | 2.33 °C | 14 mm |
| April | 0.48 °C | 12.14 °C | 28 mm |
| May | 6.88 °C | 19.98 °C | 38 mm |
| June | 11.91 °C | 24.12 °C | 60 mm |
| July | 14.45 °C | 26.34 °C | 89 mm |
| August | 13.72 °C | 25.24 °C | 77 mm |
| September | 9.08 °C | 20.58 °C | 41 mm |
| October | 3.96 °C | 13.23 °C | 24 mm |
| November | -1.93 °C | 6.14 °C | 12 mm |
| December | -9.51 °C | -2 °C | 7 mm |
| Annual | 1.1 °C | 11.6 °C | 390 mm |
| 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 : -28.9°C to -26.1°C |
| Current Drought Conditions | Normal |