<p>Based on number of posts:</p>

<p>Time of day: Looks like 3:00-7:00 (all times are <a href="https://en.wikipedia.org/wiki/Coordinated_Universal_Time" rel="nofollow noreferrer">UTC</a>) is half as busy as 14:00-18:00 </p>

<p>day of week: Saturday is the least busy day, followed by Sunday</p>

<p>combined: 6:00-7:00 Saturday is just over 20% as busy as 15:00-16:00 Wednesday</p>

<p>via this query --</p>

<p><a href="http://data.stackexchange.com/stats/query/51030/posts-by-day-of-week-and-hour-of-day" rel="nofollow noreferrer">http://data.stackexchange.com/stats/query/51030/posts-by-day-of-week-and-hour-of-day</a></p>

<p><a href="https://i.stack.imgur.com/ZBTQ6.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ZBTQ6.png" alt="CrossValidated Traffic"></a></p>

<pre><code>foo &lt;- read.table("http://data.stackexchange.com/stats/csv/51030",
  sep=",",header=TRUE)[1:24,1:8]
foo$Hour &lt;- as.numeric(as.character(foo$Hour))
with(foo,plot(Hour,Monday,type="o",pch=19,
  xlab="Hour (UTC)",ylab="",ylim=range(c(0,foo[,-1]))))
for ( ii in 3:8 ) with(foo,lines(Hour,foo[,ii],type="o",pch=19,col=ii-1))
legend("bottomright",lwd=1,pch=19,col=1:7,legend=colnames(foo)[-1])
</code></pre>

<p>More practically, just avoid the very busiest times (15:00 $\pm$ 3 or 4 hours on weekdays) and if you don't do too many per day (I'd suggest you don't take up more than about a fifth of the front page with bumped posts, for example) you should be fine.</p>
