Over half the HN readership lives in areas where these abbreviations are human-readable. And 100% can google the abbreviations. Would it be better if we start

Over half the HN readership lives in areas where these abbreviations are human-readable. And 100% can google the abbreviations. Would it be better if we started using UTC+5, etc.? Sure. But good luck getting Americans to change. If the OP's European counterpart posted a time in "CET" I'd have to go look it up, and I'd be fine doing that if it was important to me, rather than pointing the finger and crying Eurocentrism. What I did find objectionable about the times, though, was the lack of "AM" or "PM". In the US, 3:00 might be in the morning or the afternoon, and the context does not make it clear which is intended.