Madrid is 6 hours ahead of Medellín
Best overlap: 8:00 AM to 12:00 PM in Medellín is 2:00 PM to 6:00 PM in Madrid.
Shoot for 8:00 AM to 12:00 PM in Medellín; your Madrid colleagues will see that as 2:00 PM to 6:00 PM. Madrid is 6 hours ahead of Medellín, so the practical overlap is about 4 hours — generous enough for meetings, tight enough to be worth booking ahead. Don't be caught out by clock changes — Madrid observes daylight saving and Medellín doesn't, so the offset varies by an hour through the year.