Delhi, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 2.2 °C (low) to 13.6 °C (high). Annual precipitation averages 1003.8 Millimeters. Delhi is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -13.2 °C | -3.4 °C | 31.5 mm |
| February | -11 °C | -0.9 °C | 33.53 mm |
| March | -4.5 °C | 6.4 °C | 54.36 mm |
| April | 1.7 °C | 14.1 °C | 100.84 mm |
| May | 8.3 °C | 20.5 °C | 120.65 mm |
| June | 14.1 °C | 25.9 °C | 151.89 mm |
| July | 15.9 °C | 27.6 °C | 120.4 mm |
| August | 14.6 °C | 26.6 °C | 114.3 mm |
| September | 9.6 °C | 23.1 °C | 98.55 mm |
| October | 3.1 °C | 15.8 °C | 77.22 mm |
| November | -3.4 °C | 7.1 °C | 58.17 mm |
| December | -9.3 °C | -0.2 °C | 42.42 mm |
| Annual | 2.2 °C | 13.6 °C | 1003.83 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 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 |