Dubuque, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 3.8 °C (low) to 14.5 °C (high). Annual precipitation averages 972.6 Millimeters. Dubuque is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -11.5 °C | -2.3 °C | 32.77 mm |
| February | -9.8 °C | 0.1 °C | 37.85 mm |
| March | -3.2 °C | 7.3 °C | 52.83 mm |
| April | 3.2 °C | 14.9 °C | 97.28 mm |
| May | 9.6 °C | 21.6 °C | 114.3 mm |
| June | 15.4 °C | 26.9 °C | 144.27 mm |
| July | 17.6 °C | 28.7 °C | 126.24 mm |
| August | 16.4 °C | 27.7 °C | 99.82 mm |
| September | 11.7 °C | 23.9 °C | 93.98 mm |
| October | 5.1 °C | 16.4 °C | 72.64 mm |
| November | -1.6 °C | 7.8 °C | 57.15 mm |
| December | -7.8 °C | 0.7 °C | 43.43 mm |
| Annual | 3.8 °C | 14.5 °C | 972.56 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 125-150 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 |