Seasons
Sign-ups usually open months before a season starts. Spring sports sign up in the fall.
Seasons are a rough guide. Leagues use them differently, and many run across two seasons. Club volleyball, for example, usually runs from winter into spring, and many swim teams practice year-round. Always check the dates on each league's card.
Fall
Usually about Aug–Nov
Winter
Usually about Dec–Feb
Spring
Usually about Feb–Jun
Summer
Usually about Jun–Aug