Istanbul is 8 hours ahead of Medellín
Best overlap: 8:00 AM to 10:00 AM in Medellín is 4:00 PM to 6:00 PM in Istanbul.
Your shared working hours run 8:00 AM to 10:00 AM in Medellín (4:00 PM to 6:00 PM in Istanbul). Because Istanbul is 8 hours ahead of Medellín, the shared window is only about 2 hours. A fixed slot at 8:00 AM in Medellín (4:00 PM in Istanbul) saves a lot of back-and-forth.