Whether you’re snowed in or just looking for a good book to curl up and read with the kids, here are some winter themed recommendations. (These are my honest recommendations. I do not profit or have affiliate links.)
Book Recommendations for K through 3rd grade:

Goodnight Moon (by Brown) (level 1.8) – A great bedtime story for anytime of the year but the illustrations hint at winter with mittens drying by a cozy fire.

Bear Snores On (by Wilson) (level 2.2) – One of my favorites for teaching rhyming words. The story and illustrations are super cute!

Pete the Cat Snow Daze (by Dean) (level 1.9) – Pete the Cat has lots of fun on his snow day off of school. But as the snow days continue, he wonders if there can be too many snow days.

The Snowy Day (by Keats) (level 2.5) – Full of wonder, a little boy plays in the first snow of winter.

Just a Snowman (a Little Critter book, by Mayer) (level 2.6) – Little Critter wants to build a snowman but must help others first. As an added bonus, kids can search for the little spider drawn on each page.

Winter on the Farm (by Wilder) (a My First Little House Book for young readers) – Great for little boys as it is told from a young boy’s perspective.

Winter Days in the Big Woods (by Wilder) (a My First Little House Book for young readers) – A little pioneer girl and her family spend the winter in their cabin. Wonderful illustrations!

Snowmen at Night (by Buehner) (about 3rd grade reading level) – Find out what snowmen do at night when they think no one is watching. It also has rhyming words.

Curious George in the Snow (by Rey) (about 3rd grade level) – One curious, little monkey can cause quite a stir in the snow.

Curious About Snow (by Shaw) (about 3rd grade reading level) – Answers a lot of questions about snow.

The Tiny Snowflake (by Ginolfi, faith based) (level 3.1) – A little snowflake discovers her purpose and what makes her special.
Book Recommendations for 4th through 7th grade:

Winter of the Ice Wizard (Magic Tree House Series by Osborne) (late 3rd to 4th grade level) – A Fantasy Series. Four kids travel to a frozen kingdom where they must overcome their fears to find Merlin and Morgan.

The Long Winter (by Wilder) (level 5.3) – How the Ingalls family gets through the hardships of a long winter.

The Lion, The Witch, and The Wardrobe (Chronicles of Narnia, by C.S. Lewis) (5th to 7th grade) – Book #2 in the fantasy series. Four children enter the land of Narnia and must help Aslan defeat the white witch.