I don't get it.... I don't get it at all...

[Clayton]

dude you are in canada! come stay with me in oklahoma in august when its 108 out side and 95% humidaty and tell me you want to slugback a dopplebock or porter

 

[DanVader]

Sam Adams seems to have cornered the market on "seasonal" marketing. With BMC you can drink piss all year, With SA you have to wait for summer.

 

[rico567]

Questions like this are rarely as simple as "this" or "that." I'm certain that seasonal beers as they are sold commercially are, to a great extent, simply that. The brewery is able to vary its offerings year-round, create anticipation for the release of a particularly popular style (e.g, the yearly release of Three Floyds' Dark Lord Stout seems to inspire what amounts to mania on the part of its devotees), and all the rest of the black art of marketing.
However, it's also pretty obvious that there is a historical element to "seasonality" in beers, relating to ingredients, or a heavier brew for monks to drink during Lent while fasting, etc. As a contemporary example, it's hard to see how the seasonal practice of wet hopping could practically occur except at the hop harvest.
As a nod to preference, there also is likely some element relating to most people prefering a lighter "saison" or lighter type beeer in Summer, while the big Winter ales, stouts, barleywines, etc. probably go over better in the cold weather.
Personally, if it's good beer, I'm good to go....pretty much any time.