Prized for its warmth, flannel is primarily popular as a winter material. You can assess how thick and heavy a flannel sheet is by the GSM, or grams per square meter. A GSM of 130 to 135 is considered lightweight, 140 to 150 is considered midweight, and 160 or more is considered heavyweight. 

SATIN Satin sheets can be made from a variety of materials including cotton, sink, polyester, or wool. This type of fabric tends to be of high quality due to its soft feel and shining appearance. Satin is also a great material for keeping warm throughout colder nights. The only downside is that these sheets can be hard to care for, and are not as durable as other varieties.