Bruin, Pennsylvania has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3.9 °C (low) to 16.2 °C (high). Annual precipitation averages 1118.6 Millimeters. Bruin is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -7.6 °C | 1.8 °C | 81.79 mm |
| February | -7.1 °C | 3.6 °C | 64.77 mm |
| March | -3.2 °C | 8.7 °C | 84.33 mm |
| April | 2.4 °C | 16.7 °C | 98.04 mm |
| May | 8.2 °C | 22.5 °C | 94.23 mm |
| June | 13.3 °C | 26.7 °C | 129.29 mm |
| July | 15.4 °C | 28.7 °C | 115.82 mm |
| August | 14.7 °C | 28.2 °C | 97.54 mm |
| September | 10.8 °C | 24.6 °C | 102.87 mm |
| October | 4.8 °C | 17.7 °C | 82.8 mm |
| November | -0.2 °C | 10.3 °C | 83.06 mm |
| December | -4.3 °C | 4.3 °C | 84.07 mm |
| Annual | 3.9 °C | 16.2 °C | 1118.61 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 1 - May 10 |
| 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 |