Sioux City, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 2.9 °C (low) to 15.3 °C (high). Annual precipitation averages 739.4 Millimeters. Sioux City is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -12.3 °C | -1.6 °C | 16 mm |
| February | -9.9 °C | 1.2 °C | 19.81 mm |
| March | -3.8 °C | 8.5 °C | 40.13 mm |
| April | 2.3 °C | 15.9 °C | 80.52 mm |
| May | 9.2 °C | 22.1 °C | 103.12 mm |
| June | 15.3 °C | 27.7 °C | 114.05 mm |
| July | 17.4 °C | 29.6 °C | 84.33 mm |
| August | 15.9 °C | 28.3 °C | 87.88 mm |
| September | 10.7 °C | 24.9 °C | 76.2 mm |
| October | 3.5 °C | 17.6 °C | 58.93 mm |
| November | -3.8 °C | 8.5 °C | 34.04 mm |
| December | -9.5 °C | 1 °C | 24.38 mm |
| Annual | 2.9 °C | 15.3 °C | 739.39 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| 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 | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |