Mason City, Nebraska has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 2.4 °C (low) to 16.7 °C (high). Annual precipitation averages 658.9 Millimeters. Mason City 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 | -10.8 °C | 2.4 °C | 13.46 mm |
| February | -9.2 °C | 4.4 °C | 17.02 mm |
| March | -4.1 °C | 10.7 °C | 36.83 mm |
| April | 1.4 °C | 16.3 °C | 75.44 mm |
| May | 7.8 °C | 21.8 °C | 104.65 mm |
| June | 13.9 °C | 27.4 °C | 95.25 mm |
| July | 16.8 °C | 30.5 °C | 82.04 mm |
| August | 15.4 °C | 29.4 °C | 81.53 mm |
| September | 9.7 °C | 25.4 °C | 61.98 mm |
| October | 2.2 °C | 18.1 °C | 44.96 mm |
| November | -4.6 °C | 10.1 °C | 27.43 mm |
| December | -9.4 °C | 3.7 °C | 18.29 mm |
| Annual | 2.4 °C | 16.7 °C | 658.88 mm |
| 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 : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |