Brookhaven, Pennsylvania has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 47.9 °F (low) to 63.9 °F (high). Annual precipitation averages 45.8 Inches. Brookhaven is located in USDA Plant Hardiness Zone 7b. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 26.7 °F | 40.5 °F | 3.53 in. |
| February | 28.0 °F | 42.9 °F | 2.86 in. |
| March | 34.7 °F | 50.9 °F | 4.27 in. |
| April | 45.1 °F | 63.0 °F | 3.55 in. |
| May | 54.8 °F | 72.4 °F | 3.67 in. |
| June | 64.3 °F | 81.6 °F | 4.43 in. |
| July | 69.8 °F | 86.0 °F | 4.62 in. |
| August | 68.3 °F | 84.3 °F | 4.33 in. |
| September | 61.6 °F | 78.0 °F | 4.1 in. |
| October | 49.7 °F | 66.0 °F | 3.66 in. |
| November | 39.5 °F | 55.2 °F | 2.86 in. |
| December | 32.1 °F | 45.4 °F | 3.88 in. |
| Annual | 47.9 °F | 63.9 °F | 45.76 in. |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7b : 5°F to 10°F |
| Plant Hardiness Zone - 2012 | Zone 7b : 5°F to 10°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |