Hallam, Nebraska has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.7 °C (low) to 17 °C (high). Annual precipitation averages 772.2 Millimeters. Hallam is located in USDA Plant Hardiness Zone 6a. 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 | -9.3 °C | 1.9 °C | 17.53 mm |
| February | -7.1 °C | 4.1 °C | 22.61 mm |
| March | -2.1 °C | 10.9 °C | 42.16 mm |
| April | 4 °C | 17.2 °C | 67.31 mm |
| May | 10.2 °C | 22.5 °C | 137.92 mm |
| June | 16.2 °C | 28.2 °C | 113.03 mm |
| July | 18.4 °C | 30.2 °C | 98.3 mm |
| August | 17.3 °C | 29.6 °C | 83.06 mm |
| September | 12.5 °C | 25.8 °C | 72.14 mm |
| October | 5.3 °C | 19.1 °C | 58.17 mm |
| November | -1.8 °C | 10.3 °C | 33.02 mm |
| December | -7.1 °C | 3.6 °C | 26.92 mm |
| Annual | 4.7 °C | 17 °C | 772.17 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 6a : -23.3°C to -20.6°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 |