Houston is 7 hours behind Hamburg
Best overlap: 3:00 PM to 6:00 PM in Hamburg is 8:00 AM to 11:00 AM in Houston.
3:00 PM to 6:00 PM in Hamburg is when Houston is also working, at 8:00 AM to 11:00 AM their time. Houston is 7 hours behind Hamburg. That leaves about 3 hours of common time — enough for a meeting or two, so use it deliberately.