This morning drive into work was somewhat wet to say the least. My car, for once, seemed to have been behaving itself with the nice recent sunny days. However this morning it did not feel quite as responsive and MPGs were down a bit as well, which considering my drive was slower than normal seems all a bit weird.

In the past I had found the cooler weather made the car peform better, so this seems a little confusing. I am away for a few days, but I'll vag-com it when get home. In the mean time any suggestions I should/could look for?

driving in the rain causes more drag so mpg will drop, the heavier the rain the worst it will be. Not sure how moisture in the air affects the burn of the fuel either?

Air is more dense on a cold day and so volumetric efficiency is improved. This means that more air is drawn into the cylinder and hence the reason why your car seems to go better in cooler weather. The air temperature sensor's information will have an effect on fuelling but I doubt it's actually that much.....

are you sure it's not just the effect of early traction control activity pulling off power before it becomes noticeable? Try turning traction off and see if the response differs.

Personally I usually end up turning traction off in the wet as it's a right pain in the backside.