Merna, Nebraska has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 2.1 °C (low) to 16.4 °C (high). Annual precipitation averages 615.2 Millimeters. 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 | -10.4 °C | 2.7 °C | 10.92 mm |
| February | -8.9 °C | 4.4 °C | 15.49 mm |
| March | -4.1 °C | 10.4 °C | 33.02 mm |
| April | 0.9 °C | 15.4 °C | 67.82 mm |
| May | 7.2 °C | 21.1 °C | 101.35 mm |
| June | 13.3 °C | 27 °C | 95.25 mm |
| July | 16.2 °C | 30.2 °C | 83.31 mm |
| August | 14.8 °C | 29 °C | 70.36 mm |
| September | 9.3 °C | 25.1 °C | 52.32 mm |
| October | 1.7 °C | 17.7 °C | 49.02 mm |
| November | -4.9 °C | 10.1 °C | 21.84 mm |
| December | -9.4 °C | 3.8 °C | 14.48 mm |
| Annual | 2.1 °C | 16.4 °C | 615.18 mm |
| 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 : -28.9°C to -26.1°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 |