user21671: In the Bitcoin wiki:

Block times are accurate only to within an hour or two.

is a bit vague. Is it possible to prove that an arbitrary accepted block timestamp is within x seconds of the real-world time? How?

user18196: Block timestamps are whatever time the miner wants to put in there, within some loose bounds, so there isn't a real guarantee.
For more info on what those bounds are, check out this answer:

https://bitcoin.stackexchange.com/a/917/18196


21671: <p>In the <a href="https://en.bitcoin.it/wiki/Block_timestamp" rel="nofollow noreferrer">Bitcoin wiki</a>:</p>

<blockquote>
  <p>Block times are accurate only to within an hour or two.</p>
</blockquote>

<p>is a bit vague. Is it possible to prove that an arbitrary accepted block timestamp is within x seconds of the real-world time? How?</p>
 18196: <p>Block timestamps are whatever time the miner wants to put in there, within some loose bounds, so there isn't a real guarantee.</p>

<p>For more info on what those bounds are, check out this answer:</p>

<ul>
<li><a href="https://bitcoin.stackexchange.com/a/917/18196">https://bitcoin.stackexchange.com/a/917/18196</a></li>
</ul>
