Daily low temperatures increase by 6Â°F, from 37Â°F to 43Â°F, rarely falling below 30Â°F or exceeding 49Â°F. For reference, on July 30, the hottest day of the year, temperatures in West Yellowstone typically range from 46Â°F to 77Â°F, while on January 27, the coldest day of the year, they range from 7Â°F to 25Â°F.