Johnstown, Ohio has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 41 °F (low) to 60.6 °F (high). Annual precipitation averages 42 Inches. Johnstown 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 | 18.9 °F | 34.5 °F | 3.01 in. |
| February | 20.8 °F | 37.9 °F | 2.32 in. |
| March | 29.0 °F | 48.3 °F | 3.34 in. |
| April | 39.5 °F | 61.5 °F | 3.94 in. |
| May | 50.1 °F | 71.5 °F | 4.28 in. |
| June | 59.3 °F | 79.8 °F | 4.55 in. |
| July | 62.5 °F | 83.0 °F | 4.53 in. |
| August | 60.7 °F | 81.5 °F | 3.67 in. |
| September | 53.4 °F | 75.7 °F | 3.49 in. |
| October | 41.8 °F | 63.5 °F | 2.84 in. |
| November | 32.0 °F | 50.4 °F | 3.01 in. |
| December | 24.5 °F | 39.2 °F | 3.03 in. |
| Annual | 41 °F | 60.6 °F | 42.01 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |