Lyman, Nebraska has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 33.7 °F (low) to 63.5 °F (high). Annual precipitation averages 15.5 Inches. Lyman is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 14.8 °F | 40.7 °F | 0.25 in. |
| February | 16.3 °F | 43.1 °F | 0.51 in. |
| March | 24.1 °F | 52.8 °F | 0.84 in. |
| April | 31.4 °F | 60.4 °F | 1.99 in. |
| May | 41.7 °F | 70.1 °F | 2.88 in. |
| June | 51.5 °F | 82.2 °F | 2.46 in. |
| July | 57.7 °F | 89.5 °F | 1.65 in. |
| August | 55.0 °F | 87.7 °F | 1.04 in. |
| September | 45.0 °F | 78.9 °F | 1.55 in. |
| October | 31.9 °F | 64.3 °F | 1.46 in. |
| November | 21.4 °F | 50.9 °F | 0.46 in. |
| December | 14.0 °F | 41.0 °F | 0.39 in. |
| Annual | 33.7 °F | 63.5 °F | 15.48 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 5a : -20°F to -15°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 |