I've noticed we're on winter blend here too now: proof was in consistent poorer mileage following an October fillup using the same gas from the same vendor I always use, and no other changes to anything.
Not much to be done about it, unfortunately. The [censored] weather tends to reduce my driving in the winter anyway (no pleasure drives or road trips, just the essential driving), so even though I'll wind up paying more for every tank of gas (in that I'm getting fewer miles out of the winter blend), it'll be offset somewhat by the fact that I'll be doing less driving anyway, so total monthly fuel costs should even out.
Its also a slap right back at them: if they're going to give me [censored] gas in the winter that doesn't go as far, then I'm content to reduce my driving anyway so that they wind up making no more money from me in the winter than they do in the summer (and most likely, less money off me).
-Spyder