Superior, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 1.8 °C (low) to 12.9 °C (high). Annual precipitation averages 787.1 Millimeters. Superior 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 | -14.1 °C | -4.7 °C | 19.81 mm |
| February | -12.2 °C | -2.4 °C | 21.08 mm |
| March | -5.4 °C | 4.7 °C | 42.67 mm |
| April | 1.2 °C | 13.3 °C | 83.57 mm |
| May | 8.3 °C | 20.2 °C | 114.3 mm |
| June | 14.3 °C | 25.8 °C | 122.68 mm |
| July | 16.6 °C | 28.2 °C | 93.22 mm |
| August | 14.9 °C | 26.6 °C | 93.22 mm |
| September | 10.3 °C | 23.4 °C | 79.5 mm |
| October | 2.8 °C | 15.3 °C | 59.69 mm |
| November | -4.1 °C | 6.1 °C | 33.27 mm |
| December | -10.9 °C | -1.9 °C | 24.13 mm |
| Annual | 1.8 °C | 12.9 °C | 787.14 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 | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |