According to the 2023 USDA Hardiness Zone Map Lower Keys in Monroe County, Florida is in Zones 10a (30°F to 25°F), 10b (35°F to 30°F), 11a (40°F to 35°F), 11b (45°F to 40°F) and 12a (50°F to 45°F). This is a change from the 2012 USDA Hardiness Zone Map which has Lower Keys in Monroe County in Zones 10a (30°F to 25°F), 10b (35°F to 30°F), 11a (40°F to 35°F) and 11b (45°F to 40°F).