This again is close to unprecedented. As you'd expect, the electorate remains highly divided in the days just after a presidential election and then has a rally on effect as the national pageantry of the change of power accelerates. The opposite is happening with Trump.
We now have two good apples to apples approval measures for Trump's transition.
Gallup tested Trump approval in the second week of December and got 48%-48%. In early January the number had fallen to 44% approve, 51% disapprove.
Today's CNN poll has another before and after. In mid-November 46% approved and 45% disapproved, against basically tied. In the poll just out today it's 40% approve, 52% disapprove.
These numbers aren't just double digits behind all his recent predecessors - at the same period, Obama was at 83%, Bush at 61% and Clinton at 68%. Most got more popular through their transitions. Trump's getting more unpopular as he goes.