Cromwell, 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 15.1 °C (high). Annual precipitation averages 970.8 Millimeters. Cromwell 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 | -8.2 °C | -0.2 °C | 61.98 mm |
| February | -7 °C | 1.9 °C | 53.34 mm |
| March | -2.4 °C | 8.2 °C | 56.64 mm |
| April | 3.6 °C | 15.4 °C | 91.95 mm |
| May | 9.9 °C | 21.4 °C | 111.25 mm |
| June | 15.2 °C | 26.4 °C | 107.19 mm |
| July | 17 °C | 28.3 °C | 97.03 mm |
| August | 15.9 °C | 27.2 °C | 100.84 mm |
| September | 11.9 °C | 24.1 °C | 78.49 mm |
| October | 5.8 °C | 17.2 °C | 80.01 mm |
| November | 0.2 °C | 9.3 °C | 75.44 mm |
| December | -4.8 °C | 2.5 °C | 56.64 mm |
| Annual | 4.8 °C | 15.1 °C | 970.8 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 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 |