@gemlog Bless the British Empire and the People's Republic, Hong Kong has never suffered that nonsense. We're on UTC+8 all year round.
We're about five degrees west of 120Β°E, geographical UTC+8, so we're on 20 minutes "permanent daylight saving" (and so is Beijing), so sunset is not centered around 18, it's at 17:40 at winter solstice and at 19:00 at summer solstice, and that's why we weren't at 18:00 already at equinox.