Brookside, Delaware has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 7.3 °C (low) to 18 °C (high). Annual precipitation averages 1211.1 Millimeters. Brookside 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 | -4.2 °C | 5 °C | 87.38 mm |
| February | -3.8 °C | 6.4 °C | 73.41 mm |
| March | 0.2 °C | 10.9 °C | 109.22 mm |
| April | 6 °C | 17.7 °C | 92.46 mm |
| May | 11.4 °C | 22.9 °C | 97.03 mm |
| June | 16.5 °C | 27.9 °C | 120.14 mm |
| July | 19.4 °C | 30.3 °C | 120.14 mm |
| August | 18.6 °C | 29.3 °C | 107.19 mm |
| September | 14.7 °C | 25.9 °C | 113.54 mm |
| October | 7.8 °C | 19.3 °C | 103.12 mm |
| November | 2.3 °C | 13 °C | 82.04 mm |
| December | -1.6 °C | 7.4 °C | 105.41 mm |
| Annual | 7.3 °C | 18 °C | 1211.08 mm |
| 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 : -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 |