Petrolia, Pennsylvania has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3.8 °C (low) to 16 °C (high). Annual precipitation averages 1128.3 Millimeters. Petrolia is located in USDA Plant Hardiness Zone 6a. 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 | -7.7 °C | 1.6 °C | 84.07 mm |
| February | -7.1 °C | 3.3 °C | 65.79 mm |
| March | -3.2 °C | 8.5 °C | 84.07 mm |
| April | 2.4 °C | 16.7 °C | 100.33 mm |
| May | 8.2 °C | 22.4 °C | 96.01 mm |
| June | 13.1 °C | 26.6 °C | 129.54 mm |
| July | 15.2 °C | 28.6 °C | 115.57 mm |
| August | 14.4 °C | 28.1 °C | 97.03 mm |
| September | 10.6 °C | 24.5 °C | 103.12 mm |
| October | 4.7 °C | 17.7 °C | 82.8 mm |
| November | -0.3 °C | 10.1 °C | 83.57 mm |
| December | -4.4 °C | 4.1 °C | 86.36 mm |
| Annual | 3.8 °C | 16 °C | 1128.26 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |