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