According to the 2023 USDA Hardiness Zone Map Riverside County, California is in Zones 10a (30°F to 25°F), 10b (35°F to 30°F), 6a (-10°F to -5°F), 6b (-5°F to 0°F), 7a (0°F to 5°F), 7b (5°F to 10°F), 8a (10°F to 15°F), 8b (15°F to 20°F), 9a (20°F to 25°F) and 9b (25°F to 20°F). This is a change from the 2012 USDA Hardiness Zone Map which has Riverside County in Zones 6b (-5°F to 0°F), 7a (0°F to 5°F), 7b (5°F to 10°F), 8a (10°F to 15°F), 8b (15°F to 20°F), 9a (20°F to 25°F), 9b (25°F to 20°F), 10a (30°F to 25°F) and 10b (35°F to 30°F).