Monona, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 2.3 °C (low) to 13.2 °C (high). Annual precipitation averages 978.9 Millimeters. Monona 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 | -13.2 °C | -3.9 °C | 29.46 mm |
| February | -11.4 °C | -1.4 °C | 30.23 mm |
| March | -4.7 °C | 5.8 °C | 53.34 mm |
| April | 1.8 °C | 13.7 °C | 103.89 mm |
| May | 8.3 °C | 20.3 °C | 124.21 mm |
| June | 14.4 °C | 25.7 °C | 150.62 mm |
| July | 16.3 °C | 27.5 °C | 116.84 mm |
| August | 14.9 °C | 26.5 °C | 108.2 mm |
| September | 10.3 °C | 22.8 °C | 98.55 mm |
| October | 3.4 °C | 15.6 °C | 73.41 mm |
| November | -3.1 °C | 6.5 °C | 51.56 mm |
| December | -9.4 °C | -0.7 °C | 38.61 mm |
| Annual | 2.3 °C | 13.2 °C | 978.92 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 | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |