Madrid is 7 hours behind Shenzhen
Best overlap: 3:00 PM to 6:00 PM in Shenzhen is 8:00 AM to 11:00 AM in Madrid.
The best time to meet is 3:00 PM to 6:00 PM in Shenzhen, which is 8:00 AM to 11:00 AM in Madrid. The overlap sits at about 3 hours; aim for the heart of it so the call isn't too early for one team or too late for the other. Note the seasonal wrinkle: when Madrid is on daylight saving and Shenzhen isn't, the gap between them grows or shrinks by an hour.