Difference between winter/summer mpg

[illili]

Hello all,

I just recently purchased an 04 civic hybrid and I'm averaging ~48-50 mpg. Where I live it's really cold right now (in the teens for the days I've been driving) and I was wondering if anyone had any knowledge of how different the mileage is between summer and winter driving.

I'm fairly sure that auto-stop doesn't work if things aren't properly warmed up so that's one downfall. But on my 17 mile commute to school my engine barely reaches operating temp. Also, I know that people are rather frightened of the battery packs dying, and I have my fingers crossed, but would I be correct in saying that the only reason that is a fear is because it's much easier to spread a message of negativity rather than positive? I personally have heard of hybrids going ~300,000 before the battery crapping out.

Also, any tips for driving a hybrid would be helpful as the previous cars I drove were a 94 ranger 4.0 that got 23 mpg and an 91 infiniti g20 that got 33.

Thanks in advance :]

EDIT: Does anybody know the oil capacity for this model? (04 civic hybrid)?
EDIT2: @Right lane cruiser, I have a 5 spd.


EDIT 3: This may seem like a foolish question, so pardon my ignorance, but where on this site is the place to submit mileage logs and where do I get those green signature type things with your mileage and vehicle?