cold auto battery?

So my girlfriends car wouldnt start this morning, she came in and said that it was prolly the starter. She has a 2001 VW Golf - and her starter always makes a shreaking noise when starting. I guess this is just a feature with VWs?!? Anyway, I heard her try to start her car, and it did sound like it was turning over - so it didnt seem like a starter problem to me. I put some shoes on and went to the garage and got my jumper cables. I hooked up the cars and let them sit - charging for a few minutes while we planned on ideas for the towing of her car. After a few minutes - it started up just fine. We havent used it since Friday night - so the battery just may have been affected by the big temperature drop over the weekend? Kevin gave another good tip for this situation... turn the car lights on for 15-30seconds or more before starting the car. This should get the chemicals in the battery moving so its will be more active and ready for the charging. I gotta remember to put the other set of jumper cables in my car tonight - cuz this is the season...