I know it's south facing, but what are the temps like in dec, jan, and feb?

I climbed it once in mid-January. If you hit it in the afternoon, the sun comes back out from behind Juniper Peak and gives you a couple hours of direct sunlight. I was actually climbing in my t-shirt that day.

its totally a winter climb. the first couple of pitches can be cool, as they face west, but if you dont start at the crack of dawn, you'll likely be behind a party or two. this is NBD, though- huge ledges all the way up and pleasant climbing as well.

a sunnier route would be to start via Cookie Monster, which is east facing, and climb that until you join the south and east facing pitches of Cat. This is a nice option because you can pass slower parties (routefinding is a bit weird down low), and get 3 awesome pitches in place of 2 1/2 mediocre ones.

Depends on the wind. The first time I tried "Cat in the Hat" it was a windless afternoon in February and we climbed in shirtsleeves. The next time, last January, we hit a strong wind above p3 - jacket around the ears. Unfortunately it was a buffeting wind and it increased the difficulty by 1-2 points!

The sun gets very low in December and January and as a result, Cat doesn't have much sun. Other popular so called sunny routes like Geronimo and Mr. Z are also affected by the low winter sun.

That said, if it's not windy and the temperatures are okay, you should be fine.

Jason