Firth, Nebraska has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.8 °C (low) to 17.1 °C (high). Annual precipitation averages 803.9 Millimeters. Firth is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -9.5 °C | 1.6 °C | 19.05 mm |
| February | -6.8 °C | 4.2 °C | 24.13 mm |
| March | -1.7 °C | 10.8 °C | 45.97 mm |
| April | 4.5 °C | 17.1 °C | 70.87 mm |
| May | 10.4 °C | 22.8 °C | 143 mm |
| June | 16.4 °C | 28.5 °C | 115.06 mm |
| July | 18.7 °C | 30.7 °C | 102.11 mm |
| August | 17.5 °C | 29.9 °C | 80.77 mm |
| September | 12.3 °C | 26.1 °C | 74.42 mm |
| October | 5.3 °C | 19.1 °C | 62.23 mm |
| November | -1.8 °C | 10.6 °C | 36.83 mm |
| December | -7.2 °C | 3.7 °C | 29.46 mm |
| Annual | 4.8 °C | 17.1 °C | 803.9 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |