I did something like this when I was in kindergarten. We made t-shirts, and did one design every month we were in school. Although, we did not use our hands, my teacher had different stamps. This is a fun way to teach the different months to students. The only thing to this activity is you will have to watch what children are in your class. Having a diverse class is more common now than it ever was, and some of these children do not celebrate the holidays you would think to put on there.
T-shirt or Pre-made Calender Book (whichever way you decide to go)
Stencils for shapes that are not hands (if I were teaching, I would just add the small detail before or after depending on the month)
For this activity, it might be nice to have an “Upper Level Buddy” so we do not get paint all over the classroom. Find shape you want to use for that specific month, do a demonstration. This way the students know what they should be doing. On ones like the pumpkin, add the the mouth and eyes after the paint drys. Have fun with this. The students will love to have something they made to share with their friends and family.