Although this would somewhat depend on what part of the country you live in, many consider cotton to be generally more breathable. Especially in areas where the winters are never that severe, cotton is a popular choice. However, this would not be the best choice for other parts of the country that have frequent snow storms or nippy fall winds. Parents love fleece booties in these cases because of its ability to keep a baby’s feet warm without overheating. If you want something that combines both, try a bootie that has an outer layer of fleece with a cotton lining inside, like the BirdRock Baby Fleece Booties on our list.