Delphos, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.6 °C (low) to 16.1 °C (high). Annual precipitation averages 965.2 Millimeters. Delphos 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. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -10.2 °C | 0.1 °C | 21.08 mm |
| February | -7.9 °C | 3 °C | 32.77 mm |
| March | -2 °C | 10 °C | 56.39 mm |
| April | 4.1 °C | 16.7 °C | 95.25 mm |
| May | 10.6 °C | 22.1 °C | 140.46 mm |
| June | 16.1 °C | 27.2 °C | 134.87 mm |
| July | 18.4 °C | 29.7 °C | 115.57 mm |
| August | 17.1 °C | 28.8 °C | 109.73 mm |
| September | 12.1 °C | 24.8 °C | 93.73 mm |
| October | 5.2 °C | 18.1 °C | 77.22 mm |
| November | -1.4 °C | 9.7 °C | 52.58 mm |
| December | -7.2 °C | 2.8 °C | 35.56 mm |
| Annual | 4.6 °C | 16.1 °C | 965.21 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| 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 |