Lewellen, Nebraska has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 35.8 °F (low) to 64 °F (high). Annual precipitation averages 18.6 Inches. Lewellen 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 | 13.8 °F | 40.1 °F | 0.34 in. |
| February | 17.0 °F | 43.7 °F | 0.42 in. |
| March | 24.7 °F | 54.7 °F | 0.94 in. |
| April | 33.9 °F | 63.8 °F | 2.08 in. |
| May | 44.6 °F | 71.7 °F | 2.94 in. |
| June | 55.1 °F | 82.8 °F | 3.47 in. |
| July | 60.6 °F | 88.4 °F | 2.85 in. |
| August | 58.8 °F | 86.1 °F | 2.28 in. |
| September | 49.1 °F | 78.7 °F | 1.52 in. |
| October | 35.0 °F | 65.5 °F | 1.24 in. |
| November | 22.9 °F | 51.6 °F | 0.35 in. |
| December | 14.6 °F | 40.7 °F | 0.21 in. |
| Annual | 35.8 °F | 64 °F | 18.64 in. |
| 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 : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |