Dunkirk, Indiana has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 5.3 °C (low) to 16.1 °C (high). Annual precipitation averages 1052.6 Millimeters. Dunkirk is located in USDA Plant Hardiness Zone 6a. 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 | -7.7 °C | 0.9 °C | 70.1 mm |
| February | -6.3 °C | 3.2 °C | 59.18 mm |
| March | -1.4 °C | 9.1 °C | 81.53 mm |
| April | 4.4 °C | 16.3 °C | 101.6 mm |
| May | 10.6 °C | 22.3 °C | 110.49 mm |
| June | 15.9 °C | 27.1 °C | 115.82 mm |
| July | 17.3 °C | 28.8 °C | 107.19 mm |
| August | 16.2 °C | 27.9 °C | 98.3 mm |
| September | 12.1 °C | 25.1 °C | 83.31 mm |
| October | 6.1 °C | 18.2 °C | 74.68 mm |
| November | 0.4 °C | 10.3 °C | 81.79 mm |
| December | -4.3 °C | 3.7 °C | 68.58 mm |
| Annual | 5.3 °C | 16.1 °C | 1052.57 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°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 |