Like hot cocoa and cold, snowy nights, pulling out a pair of flannel pajamas is a sign that winter is officially here. Even if you prefer sleeping naked and don't consider yourself a "pajama person," it's nice to have a cozy, comfortable pair of pjs when it's cold outside. Flannel is known to be very soft and very warm. Sometime too warm, depending on the fabric your flannel pjs are made of.

Traditionally, flannel is made from wool, cotton, or synthetic fibers. It's often brushed with fine metal bristles for extra softness. Flannel pajamas made from 100% wool can feel too warm to sleep in if you don't live in a very cold climate or if you keep the heat pumping during the winter months. But a pair made from cotton, or a mix of cotton and other lightweight fabrics, can keep you comfy and warm without overheating. Cotton also breathes well and is less likely to irritate your skin than wool.

Ditch your worn out sleep shirt. Here are the best lightweight flannel pjs to curl up in this winter.

JCrew Flannel Pajamas: $35.11 (on sale now), Nordstrom

These awesome flannel pjs are made from 100% cotton. They're soft, warm, and come in four different patterns: snowy dots, stellar snowflakes, christmas lights, and traditional stripes. Jcrew's flannel pajamas are cut in a classic loose fit, with a drawstring waistband for extra comfort. The long sleeve top is a button up style with a chest patch pocket.

Madewell Flannel Bedtime Pajamas: $75, Madewell

Spotted Leopard Flannel Bedtime PajamasMadewell

Celebrating a warm christmas this year? You can still get cozy in a pair of flannel pjs. This cute set from Madewell comes with a pair of flannel shorts and a short sleeve top. They're made of super soft cotton and come in a unique polka dot meets leopard print pattern.

Eileen West Flannel North Collar Pajama Set: $46.80, Zappos

Flannel North Collar Pajama SetEileen West

This lightweight, vintage inspired pajama set is made of 55% cotton and 45% rayon. It comes in a rose print pattern with venise lace trim around the pockets, collar, and cuffs. The long sleeve pajama top has a notch collar, a full button front placket, and a small patch pocket on the chest. The full length bottoms have a relaxed fit with an elastic waist, to keep you comfortable all night long.

Lauren Ralph Lauren Brushed Twill Sleepshirt: $35.40, Zappos

Lauren Ralph Lauren Flannel SleepshirtRalph Lauren

A lightweight flannel sleep shirt is another great way to stay comfortable this winter without overheating. This one from Ralph Lauren has a classic plaid pattern and is made of brushed cotton for extra softness. It features long sleeves, a point collar, a shirttail hemline, and the signature "LRL" monogram on the chest pocket.

Saucy Cat Flannel Pajamas: $98.00, The Cats Pjs

Saucy Cat Flannel PJsThe Cats Pajamas

Here's a pair of flannel pjs in a traditional long sleeve cut, but with a fun, modern twist. These saucy cat pajamas are the cat's meow. There's cute cats printed all over them. They're also made from 100% cotton for a roomy, comfortable fit.

Madewell Bedtime T-Shirt: $75.00, Madewell

Bedtime T-ShirtMadewell

This nightshirt from Madewell is comfortable enough to sleep in and cute enough to throw over jeans or leggins and head out the door during the day. It's made of 100% cotton and comes in a blue peri chambray color with classic white piping around the edges of the hem, sleeves, and chest pocket.