Bibliotherapy lessons with winter themed books are great for December lessons. Here is a good list of books to choose from that don’t emphasize any religion (keeping that good ol’ public school separation of church and state) but do have a theme of gratitude for this time of year. Click each title. I’ve linked either a link to amazon or a link to an activity.
Box
es for Katje by Candace Flemming
Those Shoes by Maribeth Boelts
The Quiltmakers’ Gift by Jeff Brymbeau
The Mitten Tree by Candace Cristiansen
Lily and the Paper Man by Rebecca Upjohn
Kiki’s Hats by Warren Hanson
The Biggest Snowman Ever by Steven Kroll
No Two Alike by Keith Baker
The Little Snowplow by Lora Koehler (PPT for Snowplow to use as supplement in K-1) Here is a worksheet
Max and Marla by 
Alexandra Boiger
Owl Moon by Jane Yolen