Carnegie, Pennsylvania has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6.3 °C (low) to 16.9 °C (high). Annual precipitation averages 1051.1 Millimeters. Carnegie is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -5.3 °C | 3.3 °C | 82.3 mm |
| February | -4.6 °C | 4.6 °C | 65.79 mm |
| March | -0.7 °C | 9.7 °C | 84.33 mm |
| April | 4.9 °C | 17.3 °C | 88.65 mm |
| May | 10.7 °C | 22.7 °C | 101.6 mm |
| June | 15.6 °C | 27.2 °C | 106.68 mm |
| July | 17.9 °C | 29.4 °C | 111 mm |
| August | 17.2 °C | 28.7 °C | 86.87 mm |
| September | 13.4 °C | 25.1 °C | 88.65 mm |
| October | 7.1 °C | 18.2 °C | 77.47 mm |
| November | 1.7 °C | 11.3 °C | 75.69 mm |
| December | -2.3 °C | 5.7 °C | 82.04 mm |
| Annual | 6.3 °C | 16.9 °C | 1051.07 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |