Well, here we are halfway through April, and still no sign of that long-anticipated Penguin update. Google has been hinting at rolling this thing out for many months. At one point it was supposed to happen before the end of last year, but it kept getting pushed back. Google just hasn't been ready to launch it yet.
Early last month, Google's Gary Illyes, who had been hinting at date possibilities for quite some time, said he would no longer give any timeframes as he kept being wrong.
We still don't have a timeframe, but at least we'll know when the time finally does come. Google's John Mueller said in a Google+ hangout (via Search Engine Roundtable):
I am pretty sure when we start rolling out [Penguin] we will have a message to kind of post but at the moment I don't have anything specific to kind of announce.
Waiting on Google to push the new Penguin has grown increasingly frustrating for businesses impacted by the update in the past, who have lost search visibility and traffic and have no way to recover until the next one comes. Once the next one does come, it will supposedly be continuous, meaning that sites will no longer have to wait so long to recover in the future if they make the necessary adjustments.
Read this interview Illyes did with Stone Temple a while back for more comments on the the pending update.