How is Today filter determined?

I am sitting here in Sydney - 1 am / 15/07
I choose a filter and it shows “rolling today” as 14/07
Is this because all filters assume GMT timezone? I would have thought referenced to AWS region.


Since QuickSight (and SPICE) generally use the UTC timezone, I would expect that it uses UTC for rolling dates as well.

Yes, QuickSight is only supporting UTC for now. If you want to customize your specific timezone, you will need to create a new calculated field using addDateTime()to add offset to the time column with rolling date.
We will work on the custom timezone as a new functionality in our roadmap.