For maintenance messages, could they be of the form <i>1 hour maintenance will begin when this post is $n hours old</i> - and including how old it is, like an ordinary post. eg:<p><pre><code> maintenance will begin when this post is 1 hour old
</code></pre>
This avoids users in other time zones from needing to work out what "PDT" is, and how to convert from it to their local time zone.