According to the 2023 USDA Hardiness Zone Map Plymouth County, Massachusetts is in Zones 6b (-5°F to 0°F), 7a (0°F to 5°F) and 7b (5°F to 10°F). This is a change from the 2012 USDA Hardiness Zone Map which has Plymouth County in Zones 6b (-5°F to 0°F) and 7a (0°F to 5°F).