In the default A320 if you press the F-PLN button and scroll up/down with the panel arrow keys you can see the waypoint / destination arrival times in UTC. In the above screenshot the plane has an ETA in Sydney (YSSY) runway 25 at 8:30a UTC with the current time as 1:45a UTC, so just under 7 hours.
For real-time weather the plane’s clock is usually within a few seconds of my computer’s clock. During the flight, the destination time can change a bit based on airspeed but it is fairly accurate except for flights over the poles which seems to be a bug.
The waypoint times in UTC are also usually close - in the screenshot the next waypoint 07N70 has an ETA of 2:00a UTC which is reasonably correct considering a distance of 126 NM and a speed of 498 knots (basic math - 126 / 498 * 60 = 15.18 minutes ~ 15m 11s).
I’m wondering what does the 26:00 mean under the 126.2NM in the navigation display? Shouldn’t that instead be 15:00 because the plane is about 15 minutes from that next waypoint?