Fall is my favorite season by a long shot. I prefer the cooler temperatures compared to Summer, the relative lack of humidity, and of course the colors of the leaves. In general, Fall makes me happy. When I step outside my house in October and early November, I often find myself smiling without intending to do so. The entire ambiance of the season triggers something inside of me that brings me joy and that's why I always look forward to these months more than any in the year.
When you think about it, though, it's an odd thing. Fall is a time when everything is dying. The flowers are wilting, the trees are losing their leaves, and you can feel the chill of Winter coming. For me, though, what's important is that, unlike Winter, Fall isn't a "dead" season. It may be a "dying" one, but there's still life present and quite often that life is at its most beautiful. I realize not everyone may share my opinion, but then I prefer dusk to dawn in terms of beauty, so my opinion is probably off-center anyway.
What does this have to do with RPGs? Nothing necessarily. However, I've noticed that many, if not most, pulp fantasy worlds have a strongly "autumnal" feeling to them. The best days of the world are over and "Winter" is coming. It's not here yet and there's a chance of a brief "Indian Summer" before the snows fall, but it is coming and there's nothing anyone can do to stop it. Howard's writing definitely has this quality, as does that of Lovecraft and Smith. Moorcock's stories exude this feeling, as do, at the opposite end of the spectrum, Tolkien's. One age is passing away and the new one that is dawning will be a lesser one, a "colder" one.
My Dwimmermount campaign is set in a dying world, where the best -- and worst -- days are in the past. There are no great empires or impressive civic works projects. Instead, civilization clings to the decaying glories of the past, while Chaos lurks amidst the rubble. There's no general expectation of Ragnarok or Armageddon, but instead there's resignation and, in some quarters, ennui, about the inevitable decline to which Man's civilization is succumbing. Perhaps it's just indicative of how bizarrely my mind works, but I find that, against such a background, D&D make a great deal more sense. Most of the game's tropes and conceits work better if the presumed setting is "autumnal." I also find that the actions of the player characters, for good and for ill, take on a more satisfying -- and human -- significance in this context.
I hope this makes some sense to someone other than myself.