Salem, Ohio has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 4 °C (low) to 15.5 °C (high). Annual precipitation averages 1031.7 Millimeters. Salem is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -7.8 °C | 1.1 °C | 73.91 mm |
| February | -7.3 °C | 2.8 °C | 58.17 mm |
| March | -2.9 °C | 8.1 °C | 79.5 mm |
| April | 3.1 °C | 15.6 °C | 103.89 mm |
| May | 8.4 °C | 21.4 °C | 92.96 mm |
| June | 13.6 °C | 26.1 °C | 108.2 mm |
| July | 15.7 °C | 28.1 °C | 110.74 mm |
| August | 14.5 °C | 27.4 °C | 77.98 mm |
| September | 10.8 °C | 24.1 °C | 97.54 mm |
| October | 4.7 °C | 17.3 °C | 81.28 mm |
| November | -0.1 °C | 9.9 °C | 73.91 mm |
| December | -4.5 °C | 3.9 °C | 73.66 mm |
| Annual | 4 °C | 15.5 °C | 1031.74 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |