Bryn Mawr, Pennsylvania has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 7.6 °C (low) to 17.4 °C (high). Annual precipitation averages 1217.2 Millimeters. Bryn Mawr is located in USDA Plant Hardiness Zone 7b. 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 | -4.1 °C | 4.3 °C | 88.65 mm |
| February | -3.3 °C | 5.7 °C | 72.9 mm |
| March | 0.3 °C | 10.3 °C | 110.24 mm |
| April | 6.1 °C | 16.9 °C | 92.96 mm |
| May | 11.4 °C | 22.2 °C | 102.62 mm |
| June | 16.7 °C | 27.3 °C | 111.25 mm |
| July | 19.7 °C | 29.8 °C | 113.03 mm |
| August | 18.9 °C | 28.8 °C | 122.94 mm |
| September | 15.2 °C | 25.2 °C | 112.27 mm |
| October | 8.6 °C | 18.4 °C | 99.06 mm |
| November | 3 °C | 12.4 °C | 80.52 mm |
| December | -1.1 °C | 6.9 °C | 110.74 mm |
| Annual | 7.6 °C | 17.4 °C | 1217.18 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 7b : -15°C to -12.2°C |
| Plant Hardiness Zone - 2012 | Zone 7a : -17.8°C to -15°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |