Autumn is a lovely time of the year, full of colours and moods. BUT! This time of the year the humidity will rise markedly compared to summer. As we know, paper absorbs moisture readily, as a result the paper surface will be quite soft to what you were normally used to. Try to store your paper in a dry place but away from heat as you don't want to dry it totally which will result in brittle paper!
So be careful with those sharp points on your pencils!
Happy Painting :)