I agree. The "S" is for "standard" though, not Summer. They could have just as well put an "N" there fir "normal" or something, but the upshot is that "S" is for dry conditions and the "W" is for slippery conditions.
One other neat thing about running in "W" mode is that the car will hold itself going uphill very nicely. Try stopping going up a steep hill sometime in W, then switch over the switch to S, it'll start rolling back. OK, don't do this alot though, but it is kinda fun, as long as no one is behind you!!

Gilly