Does Winsor have an after school option?

Yes, Winsor offers after-school supervision. 
During a typical school year, Winsor offers after-school supervision until 5:30 p.m. for all Lower School students at no charge with the goal of providing a safe environment for students to work and play. Upper School students can remain on campus for after-school study, and are welcome to use the Fitness Center, and must arrange for departure before 6:00 p.m..