Brooklyn, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 3.7 °C (low) to 14.8 °C (high). Annual precipitation averages 947.4 Millimeters. Brooklyn is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -11.3 °C | -2.3 °C | 27.94 mm |
| February | -9.5 °C | 0.4 °C | 35.05 mm |
| March | -3.3 °C | 7.7 °C | 54.1 mm |
| April | 2.9 °C | 15.3 °C | 91.44 mm |
| May | 10 °C | 21.8 °C | 120.4 mm |
| June | 16.1 °C | 27.3 °C | 139.7 mm |
| July | 17.8 °C | 29.2 °C | 110.74 mm |
| August | 16.2 °C | 28.2 °C | 110.74 mm |
| September | 11.2 °C | 24.2 °C | 91.19 mm |
| October | 4.6 °C | 16.8 °C | 73.91 mm |
| November | -2.2 °C | 8.2 °C | 53.34 mm |
| December | -7.9 °C | 0.9 °C | 38.86 mm |
| Annual | 3.7 °C | 14.8 °C | 947.41 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |