Plattsmouth, Nebraska has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.5 °C (low) to 16.7 °C (high). Annual precipitation averages 833.6 Millimeters. Plattsmouth 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 | -10.4 °C | 0.4 °C | 20.32 mm |
| February | -8.2 °C | 3.3 °C | 24.89 mm |
| March | -2.2 °C | 10.6 °C | 45.21 mm |
| April | 3.9 °C | 17.3 °C | 88.14 mm |
| May | 10.7 °C | 22.9 °C | 132.59 mm |
| June | 16.5 °C | 28.4 °C | 129.03 mm |
| July | 18.8 °C | 30.2 °C | 91.95 mm |
| August | 17.3 °C | 29.4 °C | 95 mm |
| September | 11.9 °C | 25.8 °C | 76.2 mm |
| October | 5 °C | 18.8 °C | 64.26 mm |
| November | -2.2 °C | 9.9 °C | 38.35 mm |
| December | -7.7 °C | 3 °C | 27.69 mm |
| Annual | 4.5 °C | 16.7 °C | 833.63 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 125-150 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 |