Real-time availability follows the time zone of your computer. In most cases this matches the time zone set on your collection domain, so the data lines up as expected.
If you travel to a different time zone, your computer's clock no longer matches your collection domain, and you may not see the latest real-time data. To restore access, set your computer's time zone to match your collection domain, and your analyses will show the most recent data again.
To better understand the behaviour of your visitors based on their own time zone, you can also use the Device hour property.