According to the 2023 USDA Hardiness Zone Map Fern Acres, Hawaii is in Zones 11b (45°F to 40°F) and 12a (50°F to 45°F). There is no change from the 2012 USDA Hardiness Zone Map which has Fern Acres in also in Zones 11b (45°F to 40°F) and 12a (50°F to 45°F).