According to the 2023 USDA Hardiness Zone Map Lebanon, New Hampshire is in Zones 5a (-20°F to -15°F), 5a (-20°F to -15°F) and 5b (-15°F to -10°F). This is a change from the 2012 USDA Hardiness Zone Map which has Lebanon in Zones 5a (-20°F to -15°F).