Congress, Ohio has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 4.6 °C (low) to 15.1 °C (high). Annual precipitation averages 1027.2 Millimeters. Congress 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 | -7.7 °C | 0.7 °C | 72.64 mm |
| February | -7 °C | 2.3 °C | 54.61 mm |
| March | -2.5 °C | 7.7 °C | 75.95 mm |
| April | 3.6 °C | 15.3 °C | 95.25 mm |
| May | 9.4 °C | 21.1 °C | 105.16 mm |
| June | 14.7 °C | 26 °C | 113.03 mm |
| July | 16.4 °C | 27.9 °C | 102.87 mm |
| August | 15.5 °C | 27.1 °C | 96.27 mm |
| September | 11.6 °C | 23.8 °C | 86.61 mm |
| October | 5.5 °C | 16.8 °C | 80.26 mm |
| November | 0.2 °C | 9.7 °C | 73.66 mm |
| December | -4.3 °C | 3.3 °C | 70.87 mm |
| Annual | 4.6 °C | 15.1 °C | 1027.18 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 |