This is a really old question, but bumping just in case there is an update. I want users to see the time that sensor data was collected, not the time that it happened to be in a different part of the world.
My failure was trying to pass plotly the data as milliseconds since the UTC epoch. It seems that plotly somehow finds the timezone of the browsers computer and subtracts that timezone so that, say, 1764247200000 displays as a different time depending on where the user lives.
If I convert the milliseconds to strings, however, e.g. “2025-11-27 10:00:00”, or “2025-11-27T10:00:00Z” then plotly does not subtract the timezone. I find this very odd. So is the conclusion that date format must always be strings? Or maybe a configuration setting to tell Plotly to not do the subtraction??