[petek]

I think that what goes on where the proverbial tire meets the road is a matter of trying to maximize the number of points of contact. On a dry road (or a wet one where the tire is not hydroplaning), the tire is in contact with the pavement in a lot of little spots - remember that even a smooth road has a pretty rough texture, so for a given contact patch area, the tire is only touching pavement in a fraction of the patch.

Everything being equal, it seems to me that a warmer tire will conform to the road surface, macroscopically and microscopically, better than a cold one.

When you throw rain into the equation, you have to get the tire to move the water out of the way so that it can touch pavement. That's what tread is for and why dry race tires are usually slick, intermediate rain tires have shallow and narrow grooves (to channel water out, but still have a lot of contact area) and full rains have deep and wide grooves (to pump the water out in buckets).

So my answer to your original question is: a warm one, with good tread.