Brook, Indiana has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.8 °C (low) to 16 °C (high). Annual precipitation averages 1006.1 Millimeters. Brook is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -8.7 °C | 0.1 °C | 58.42 mm |
| February | -7 °C | 2.6 °C | 50.29 mm |
| March | -1.7 °C | 9.1 °C | 65.28 mm |
| April | 3.8 °C | 16.6 °C | 97.79 mm |
| May | 10.3 °C | 22.7 °C | 107.95 mm |
| June | 15.6 °C | 27.6 °C | 128.78 mm |
| July | 17.3 °C | 28.9 °C | 118.36 mm |
| August | 16.2 °C | 28.1 °C | 91.69 mm |
| September | 11.8 °C | 25.5 °C | 80.01 mm |
| October | 5.5 °C | 18.4 °C | 81.53 mm |
| November | -0.2 °C | 9.8 °C | 67.31 mm |
| December | -5.5 °C | 2.9 °C | 58.67 mm |
| Annual | 4.8 °C | 16 °C | 1006.08 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°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 |