These sheets are for winter. Recently, I learned that they are called flannel sheets. I didn't know that there are thicker winter sheets. They are 100% cotton and of good quality, but they have a very thick and somewhat fuzzy weave. I don't know how to describe them. If you know what flannel sheets are, these are it. It doesn't appear in the photo that they are for winter, nor is it mentioned in the product description (unless I missed it). I didn't return them because I got tired of the process. I hope to use them in the winter.