The four seasons give us the big picture. Spring is warm and light, Summer is cool and soft, Autumn is warm and rich, and Winter is cool and striking. Each season then divides into three, because very few of us sit neatly in the middle. Your dominant Munsell quality decides your sub-season, which is why a Soft Summer and a Soft Autumn have more in common with each other than either has with a Bright Winter.
The seasons also flow into one another in a full circle. Bright Spring borders Bright Winter, Light Spring borders Light Summer, Soft Summer borders Soft Autumn, and Dark Autumn borders Dark Winter. If you have ever felt torn between two seasons, look at its neighbour first. Each palette is a reference, not a rule: hold a garment near your face in daylight and trust what you see.