Fort Calhoun, 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 16.2 °C (high). Annual precipitation averages 824.2 Millimeters. Fort Calhoun is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -10.4 °C | -0.1 °C | 18.8 mm |
| February | -8.3 °C | 2.7 °C | 23.37 mm |
| March | -2.3 °C | 9.7 °C | 45.47 mm |
| April | 3.8 °C | 16.8 °C | 81.03 mm |
| May | 10.7 °C | 22.6 °C | 123.19 mm |
| June | 16.7 °C | 28.2 °C | 129.03 mm |
| July | 18.8 °C | 30.1 °C | 89.15 mm |
| August | 17.3 °C | 28.9 °C | 103.63 mm |
| September | 12.2 °C | 25.5 °C | 81.28 mm |
| October | 5.1 °C | 18.3 °C | 61.21 mm |
| November | -1.9 °C | 9.6 °C | 35.05 mm |
| December | -7.6 °C | 2.3 °C | 33.02 mm |
| Annual | 4.5 °C | 16.2 °C | 824.23 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| 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 | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |