According to the 2023 USDA Hardiness Zone Map Harding-Birch Lakes, Alaska is in Zones 2a (-50°F to -45°F), 2b (-45°F to -40°F), 3a (-40°F to -35°F), 3b (-35°F to -30°F) and 4a (-30°F to -25°F). This is a change from the 2012 USDA Hardiness Zone Map which has Harding-Birch Lakes in Zones 2b (-45°F to -40°F), 3a (-40°F to -35°F) and 3b (-35°F to -30°F).