I live in central florida, and we've had a pretty gentle winter this year, but I have noticed that on days that it is colder out like today, my traction control and check engine lights are far more likely to turn on. Last night it got down to 33* and this morning both lights came on.

Does anyone else have an HHR that isn't cold tolerant?

 

That's rather strange. I would check connections to see if there are any loose.. You shouldn't get these regardless of temp.

 

33 that's not cold, mine ran good till it dropped down to -19 F then had to give it more gas to go, luckily we were pointing down hill at that point, so the temp rose to -17 F ran perfect again. I was thankful, 4am on the continental divide -19 below, not a good place to stop. There must be something trying to mess up there. Have you checked for a code in there ?