Cairnbrook, Pennsylvania has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 3.4 °C (low) to 13.5 °C (high). Annual precipitation averages 1065.3 Millimeters. Cairnbrook 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 | -8.2 °C | 0.6 °C | 77.22 mm |
| February | -7.6 °C | 1.8 °C | 75.44 mm |
| March | -3.8 °C | 6.4 °C | 89.15 mm |
| April | 2.4 °C | 13.7 °C | 84.07 mm |
| May | 7.8 °C | 19.1 °C | 112.01 mm |
| June | 12.4 °C | 23.3 °C | 105.41 mm |
| July | 14.8 °C | 25.4 °C | 98.55 mm |
| August | 13.9 °C | 24.7 °C | 92.46 mm |
| September | 9.9 °C | 21.2 °C | 100.33 mm |
| October | 4.4 °C | 14.8 °C | 81.03 mm |
| November | -1 °C | 8.3 °C | 71.63 mm |
| December | -4.8 °C | 2.9 °C | 77.98 mm |
| Annual | 3.4 °C | 13.5 °C | 1065.28 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 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |