According to the 2023 USDA Hardiness Zone Map Portland, Oregon is in Zones 8a (10°F to 15°F), 8b (15°F to 20°F), 8b (15°F to 20°F), 9a (20°F to 25°F) and 9a (20°F to 25°F). This is a change from the 2012 USDA Hardiness Zone Map which has Portland in Zones 8b (15°F to 20°F) and 9a (20°F to 25°F).