I'm in Northern California and I'm seeing something similar, but not quite so bad (around 27-29). I get pretty bad gas mileage on my 15 minute commute in the mornings BUT, when there's traffic, I get much better. I also notice my engine coolant is too cold light come on in the mornings during the first part of my commute. I wonder if we can install an EBH like the prius owners to help with this? I'm guessing the short trips in the cold are killing your gas mileage.