Gabe Souza , Nov 18, 2008; 05:39 p.m.
I shoot HS football in Maine, in the freezing cold quite frequently (it was 27 for the high here the other day) and although I use Nikon, there won't be any difference. Your Pentax will be just fine in the cold. I'd only worry about it once you got down to 0 or below. The only things to be wary, as you already know, is about batteries. Those drain very fast in the cold weather...not sure what type your Pentax takes, but I know some of the Pentax's take Double A's in which case you might want more than one backup set. Even my D2H which has excellent battery life drains faster in the colder weather. And keep your batteries close to your body. If you have a coat with inside pockets, that's the place to keep them and they will stay warmer and last longer that way.
Good luck and happy shooting, and don't forget about keeping yourself warm, hard to press the shutter when you're shivering!