Time.is
I like Time.gov, personally; it was the first site I ever found around this concept and so it has a soft spot.I keep finding all my physical atomic clock synced clocks (yes, I have more than one, they are cheap these days) disagreeing, sometimes by 2 seconds or more, which makes me laugh (great ideas ruined by poor implementation).  I find many of the web sites (listed in comments or the original post) to also differ, perhaps for similar reasons of implementation choices.I would presume all the sites work off various implementations of NTP, http://www.ntp.org/ plus some trusted source.I guess my question is: has anyone found a site which is really, really accurate by reducing all the latency and lag, so what you see on the screen really is, to whatever precision, accurate?  And would said person have access to a really good source for the comparison point?  I don't seem to have one.  Yes, I should have stopped at 3 so that I could pick the 2 closest ones (like the old saying: 1 clock is unsure, 2 clocks are worse, but 3 at least lets you make a decision)I wonder, would you need to have NTP on the client side synced to a trusted source (say, in java, flash, or javascript) to get a good reading?  Any server serving over HTTP induces lag, I would think, and NTP is supposed to account for transmission delays, or so I recall.Thanks for sharing, another interesting time site to add to the collection.