According to the 2023 USDA Hardiness Zone Map Little Bitterroot Lake, Montana is in Zones 4a (-30°F to -25°F), 4b (-25°F to -20°F), 5a (-20°F to -15°F) and 5b (-15°F to -10°F). This is a change from the 2012 USDA Hardiness Zone Map which has Little Bitterroot Lake in Zones 4b (-25°F to -20°F).