Frogs warm winter book

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