Montreal is 12 hours behind Beijing

There is no standard 8-to-6 overlap. Someone joins early or late.

Practically speaking, Beijing and Montreal never share office hours; 12 hours of separation keeps their days apart. To talk live, someone has to flex: an early start in Montreal can catch the tail end of the day in Beijing, or the other way round. Note the seasonal wrinkle: when Montreal is on daylight saving and Beijing isn't, the gap between them grows or shrinks by an hour.