Sumner, Nebraska has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 2.9 °C (low) to 17.1 °C (high). Annual precipitation averages 609.4 Millimeters. Sumner is located in USDA Plant Hardiness Zone 5b. 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 | -10 °C | 2.9 °C | 10.16 mm |
| February | -8.4 °C | 5.1 °C | 15.75 mm |
| March | -3.5 °C | 11.2 °C | 33.02 mm |
| April | 1.9 °C | 16.7 °C | 63.25 mm |
| May | 8.1 °C | 22.2 °C | 102.11 mm |
| June | 14.2 °C | 28 °C | 95.76 mm |
| July | 16.8 °C | 30.6 °C | 83.82 mm |
| August | 15.6 °C | 29.3 °C | 76.45 mm |
| September | 10.1 °C | 25.8 °C | 46.74 mm |
| October | 2.7 °C | 18.7 °C | 43.94 mm |
| November | -4.2 °C | 10.6 °C | 22.35 mm |
| December | -9.1 °C | 4.2 °C | 16 mm |
| Annual | 2.9 °C | 17.1 °C | 609.35 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 5b : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |