This is off-topic, but I need to get something off my chest. There are a lot of people out there who don’t understand how time zones work. It’s a bit of a pet peeve of mine.
Just a bit ago, I received a work email where the sender (who lives in another part of the country) repeatedly said such and such meeting will be at 9:00 AM Eastern Daylight Time (UTC-4). Now, it would have been bad enough if he had just said “9:00 AM EDT”, but he took the time to spell out what EDT means and what its offset from UTC was.
For those of you who don’t know, UTC is Universal Coordinated Time (it’s UTC not UCT because the actual phrase is French). UTC is the globally recognized reference time. It’s also, just FYI, the time that your computer runs on internally, regardless of what time it displays in the corner of your screen. This used to be known as Greenwich Mean Time (GMT) except Greenwich now observes daylight savings time (DST), so Greenwich actually changes time twice a year.
Anyway, back to EDT. What the sender of that email actually meant to say was Eastern Standard Time (EST) which has an offset of UTC-5, meaning EST is five hours behind UTC. EST is the local time zone where this guy lives and works (at least until the US switches to DST in March).The difference is that EDT is EST with the daylight savings time corrector added for the months of March through October (roughly speaking). In other words, if you live in the eastern United States, you should see the sun at its apex at roughly noon EST no matter what time of year it is. Noon EDT on the other hand occurs one hour after the sun is at its apex regardless of what time of year it is.
Why does this matter? Because what he actually said, if I’m to take him at his word, is that the meeting will be at 8:00 AM local time. If I had put his appointment in my computer’s calendar with 9:00 AM EDT as the time, I would have gotten a reminder about an hour and 45 minutes before the meeting started. That’s a problem, especially if I manually convert his time into my local time by adjusting his offset to my current local UTC offset (UTC-7). Why would I do that? Let’s just say I already do that a lot with my job so I do it without consciously thinking about it.
So don’t be that guy. If you mean something will happen at 9:00 AM your local time, just say “the meeting will be at 9:00 AM my time” or “the meeting will be at 9:00 AM Eastern Time.” If you feel you absolutely must use the three letter abbreviation, then for goodness sake, know the difference between EDT and EST and use the correct one.