T.W.
Those ages are hard in the winter. When my kids were little I bought a sled I could pull with a rope around the neighborhood with them in it.
Also build a snowman, make snow angels. I also had snowball and snow brick makers to make snow forts--my kids loved that. You can put colored water in a spray bottle and paint the snow.
Then of course after all the cold fun hot chocolate is a must!
Congratulations on being a SAHM--you won't regret it!
Have fun:)