The w3c has various time specifications for time & date, but there seems to be a lack of use and/or implementation.
There’s just no good excuse, given that a browser should recognize time values when present, and have awareness of the locale information of the operating system/user, for anyone to see “5:00 PST” or the like.
There’s no reason that today’s lunar eclipse times posted on the Wikipedia entry should include a table of various timezones.
Okay, I’m a little off with that statement. If you are planning to view in a timezone other than your own, or to relay that information to someone in another timezone. But, even then I believe you should be responsible for the conversion.
So what’s the alternative, everything in UTC/GMT? No.
The alternative is responsible implementations that allow aware browsers to display ALL time values converted to your local time.
In other words you should always expect a time value to be local to your current time locale.
So how does that work? It’s dead simple and requires only one change. It works by having well-formed time values with accompanying tags or markup that designate they are time values.
Given some string which is marked as time, the browser makes a best-effort parse to understand that string, and then displays in its place whatever preference the User (you) have for time display.
It is trivial to do this correctly, yet it’s not done.