Greenwich, Ohio has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.7 °C (low) to 15.4 °C (high). Annual precipitation averages 1029.2 Millimeters. Greenwich 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 | -7.7 °C | 0.7 °C | 73.66 mm |
| February | -7 °C | 2.3 °C | 55.12 mm |
| March | -2.5 °C | 7.7 °C | 73.66 mm |
| April | 3.4 °C | 15.4 °C | 99.31 mm |
| May | 9.5 °C | 21.6 °C | 103.12 mm |
| June | 14.7 °C | 26.3 °C | 111.76 mm |
| July | 16.6 °C | 28.3 °C | 105.41 mm |
| August | 15.7 °C | 27.4 °C | 97.03 mm |
| September | 11.7 °C | 24.2 °C | 86.87 mm |
| October | 5.7 °C | 17.2 °C | 79.5 mm |
| November | 0.3 °C | 9.7 °C | 74.68 mm |
| December | -4.4 °C | 3.5 °C | 69.09 mm |
| Annual | 4.7 °C | 15.4 °C | 1029.21 mm |
| 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 : -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 | Dfa - Humid Continental Hot Summers With Year Around Precipitation |