Nature is constantly breaking things down and building them again. It is alive. There is a constant renewal in creation as the seasons circle around again and again. Every winter has its cold, but no two snowflakes are alike. We two-leggeds can't begin to comprehend such a thing.
Traditional ways are spring, summer, fall and winter.
They are forms of power. The spirits that move within them can move differently from time to time. If they did not, every day would be exactly like every other day. Every storm would be the same storm. Every leaf would be the same as every other leaf.