They've never been awful. At least on average, anyway. I'm sure there were polls out there that had him with a bad approval rating - but overall, Obama has consistently pulled in respectable numbers. Even when he was having an awful summer last year.
Using RealClearPolitics' approval ratings
http://www.realclearpolitics.com/epolls/other/president_obama_job_approval-1044.html">average, Obama's approval has fallen below 45% roughly three times in his presidency and they never stayed that low for long.
That tells me Obama's floor is probably 45% - which is remarkable with how difficult things have been in his presidency the last two years and few months.
More impressively, though, is that Obama has generally led Republicans wire-to-wire. There have been some instances where the a certain Republican will bump ahead of Obama, but no candidate has been able to hold on to their lead over Obama.
Huckabee hasn't led against Obama since October of 2010 - in a poll done by CNN (he led by 8). Since
April of last year, Huckabee has only managed to lead Obama in a poll five times.
Romney does a bit better - but still is way behind. He last led Obama in a poll back in April, and it was a paltry 2 points. Since April of last year, Romney has led Obama a total of seven times. To compare, Obama has led Romney in 37 polls. Yes,
37.
After that, it gets ridiculous. Pawlenty, Trump, Palin, Daniels, Bachmann or Paul have never led Obama in a reputable national poll. Gingrich has done it once. All the way back July 2010.
Folks, you can't dismiss those numbers. No candidate consistently even proves they're capable of being in the same ring as Obama, let alone capable of winning.
So while his approval numbers aren't awesome, his overall position is extremely strong heading into reelection. I'd even wager he's in better position than any candidate since Nixon.