Petrolia, Ontario climate data is summarized below. Average annual temperatures range from 3.6 °C (low) to 14 °C (high). Annual precipitation averages 305 Millimeters. Petrolia is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -8.66 °C | -1.06 °C | 8 mm |
| February | -9.5 °C | -1.29 °C | 1 mm |
| March | -3.64 °C | 6.17 °C | 19 mm |
| April | 1.9 °C | 13.84 °C | 30 mm |
| May | 8.06 °C | 20.71 °C | 39 mm |
| June | 13.14 °C | 25.66 °C | 35 mm |
| July | 15.68 °C | 27.75 °C | 40 mm |
| August | 14.95 °C | 26.84 °C | 50 mm |
| September | 10.52 °C | 22.55 °C | 31 mm |
| October | 5.63 °C | 15.77 °C | 26 mm |
| November | -0.08 °C | 8.64 °C | 18 mm |
| December | -4.63 °C | 2.06 °C | 8 mm |
| Annual | 3.6 °C | 14 °C | 305 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Normal |