Plano, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.4 °C (low) to 15.8 °C (high). Annual precipitation averages 983.7 Millimeters. Plano is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -10.2 °C | -0.2 °C | 28.19 mm |
| February | -8.1 °C | 2.5 °C | 37.59 mm |
| March | -2.2 °C | 9.6 °C | 56.64 mm |
| April | 3.8 °C | 16.3 °C | 100.84 mm |
| May | 10.3 °C | 21.7 °C | 137.41 mm |
| June | 15.8 °C | 27.1 °C | 135.89 mm |
| July | 18.1 °C | 29.4 °C | 115.82 mm |
| August | 16.8 °C | 28.6 °C | 107.7 mm |
| September | 11.8 °C | 24.7 °C | 97.54 mm |
| October | 5.1 °C | 17.7 °C | 74.42 mm |
| November | -1.7 °C | 9.5 °C | 53.09 mm |
| December | -7.1 °C | 2.7 °C | 38.61 mm |
| Annual | 4.4 °C | 15.8 °C | 983.74 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |