Frogs warm winter book

It's freezing and it's snowed. Frog doesn't like the cold, so he stays home alone while his friends play outside. But then the sun comes out. Frog has an idea... Frog and his friends go to Piglet's house to celebrate the New Year. But at her house, all they see is a fallen ladder and no lights in the trees. Where's Piglet? Includes Frog and the Snowman and Frog and the New Year.