Hanoi is 13 hours ahead of Calgary

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

Coordinating Calgary and Hanoi is tricky: 13 hours of separation means their standard hours don't intersect. Async-first is your friend here. Reserve real-time meetings for the rare occasions someone can log on before or after hours. Watch the DST gap — when Calgary changes its clocks and Hanoi stays the same, this window slides by an hour.