Johnstown, Nebraska has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 36 °F (low) to 60.4 °F (high). Annual precipitation averages 24 Inches. Johnstown 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 | 13.3 °F | 35.2 °F | 0.44 in. |
| February | 15.7 °F | 38.2 °F | 0.64 in. |
| March | 24.3 °F | 48.8 °F | 1.17 in. |
| April | 33.7 °F | 58.1 °F | 2.65 in. |
| May | 44.9 °F | 68.7 °F | 3.95 in. |
| June | 55.4 °F | 79.3 °F | 3.88 in. |
| July | 61.1 °F | 86.7 °F | 3.06 in. |
| August | 58.8 °F | 84.3 °F | 2.77 in. |
| September | 49.3 °F | 76.9 °F | 2.35 in. |
| October | 36.0 °F | 62.4 °F | 1.81 in. |
| November | 24.4 °F | 48.9 °F | 0.68 in. |
| December | 15.4 °F | 37.3 °F | 0.55 in. |
| Annual | 36 °F | 60.4 °F | 23.95 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°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 |