President Obama leaves after his end-of-the-year news conference at the White House on Dec. 19. (Larry Downing/Reuters)

President Obama's approval rating just hit 50 percent for the first time since the spring of 2013. That's the biggest -- and most surprising -- takeaway from a new Washington Post-ABC News poll.

The last time he hit the half-century mark was in May 2013, when WaPo-ABC and a few other pollsters showed him there just a few months into his second term.

But while other pollsters have shown Obama's approval rating getting slightly better, none have shown him recovering to the extent that this survey does. In fact, the new poll represents Obama's biggest approval bump since the mission that killed Osama bin Laden in May 2011. His approval rating has risen nine percentage points in the past month alone, while his disapproval has dropped by 10 points.

The gains are pretty even across the board, but the biggest are among Democrats (10 points), moderates (10), Hispanics (22), and even white evangelical Christians (10), who generally tilt heavily toward the GOP. Obama also has gained 19 points among adults younger than 30.

It remains to be seen how big or sustained this bump will be -- again, this is the biggest shift we've seen -- but it's undoubtedly because of the economy.

The poll shows that 41 percent of people rate the economy in a positive light, compared with 27 percent in October. Obama has the support of about three-quarters of this group.

And although Obama's ratings on the economy overlap with his overall rating (for obvious reasons), that is even more the case now. In December, 81 percent of those who approved of the president on the economy approved of him overall. Today, those two are even more closely tied, with 91 percent of those who support his economic record approving of him in general.

The poll isn't all good news for Obama, of course. The opposition to him remains more ardent than the support, with 35 percent strongly opposing him and 24 strongly supporting him. And he's still highly polarizing, with just 14 percent of Republicans approving of him (up just four points from last month), so he's still a long way from being popular.

But for a president whose second term has been marked by a steady but slight decline, he's pretty clearly headed in a different direction -- at least for now.

Peyton M. Craighill contributed to this report.