Keokuk, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6.1 °C (low) to 16.8 °C (high). Annual precipitation averages 1015.5 Millimeters. Keokuk is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -8.2 °C | 1 °C | 42.67 mm |
| February | -6.2 °C | 3.6 °C | 46.99 mm |
| March | -0.6 °C | 10.3 °C | 65.28 mm |
| April | 5.5 °C | 17.3 °C | 102.87 mm |
| May | 11.8 °C | 23 °C | 136.14 mm |
| June | 17.3 °C | 28.1 °C | 128.02 mm |
| July | 19.4 °C | 30.2 °C | 106.93 mm |
| August | 18.2 °C | 29.3 °C | 95.76 mm |
| September | 13.5 °C | 25.7 °C | 91.69 mm |
| October | 6.9 °C | 18.7 °C | 82.8 mm |
| November | 0.5 °C | 10.7 °C | 66.8 mm |
| December | -5.1 °C | 3.7 °C | 49.53 mm |
| Annual | 6.1 °C | 16.8 °C | 1015.48 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |