Merna, Nebraska has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 35.9 °F (low) to 61.5 °F (high). Annual precipitation averages 24.2 Inches. Merna is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 13.3 °F | 36.8 °F | 0.43 in. |
| February | 16.0 °F | 40.0 °F | 0.61 in. |
| March | 24.6 °F | 50.8 °F | 1.3 in. |
| April | 33.7 °F | 59.8 °F | 2.67 in. |
| May | 45.0 °F | 69.9 °F | 3.99 in. |
| June | 56.0 °F | 80.6 °F | 3.75 in. |
| July | 61.1 °F | 86.3 °F | 3.28 in. |
| August | 58.6 °F | 84.2 °F | 2.77 in. |
| September | 48.7 °F | 77.1 °F | 2.06 in. |
| October | 35.1 °F | 63.9 °F | 1.93 in. |
| November | 23.2 °F | 50.1 °F | 0.86 in. |
| December | 15.0 °F | 38.8 °F | 0.57 in. |
| Annual | 35.9 °F | 61.5 °F | 24.22 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 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 | Severe Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |