My father owned a liquor carryout/drive-thru for 30 years. I grew up around the business and worked directly on the retail side for about 10 years.
Wholesalers sell at a fixed state regulated minimum price, and retailers resell at a state regulated minimum price. Both of these prices are occasionally lowered for sale periods by the various brands, so buying wholesale while on sale, and reselling later when the sale is over, is extremely profitable for the retailer. Because of this, we would buy pallets of the major brands when they went on sale (Bud, Miller, Coors, etc ...) and store them, sometimes for months.
Since our only stock area was the unused space on the floor of the drive-thru, often times the beer would sit, effectively outdoors, for entire seasons, from one sale period, through regular price, until it went on sale again, at which point we'd finally order more. As an aside, Budweiser's "Born On Date" was conceived directly for this reason, to undercut the small retailer and return the profit margins back to the brewer by making the customer think the retailer was selling them stale beer. Bud honestly couldn't give a shit if you drank six month old beer, because you couldn't taste any difference. Anyway, consider daytime/nightime temp swings in the spring and fall, and the extremes of having beer kept in 0 degree winter temps or 100 degree summer temps, and you can imagine all sorts of ways that the beer we sold might get "skunked."
What we learned, from customer comments, directly from the distributors, and copious product quality testing by my entire family of raging alcoholics, is that temperature changes have zero effect on pasteurized beer, as well as wine coolers. You can chill it, warm it, freeze it, warm it again, and you won't be able to taste any perceivable effect if it's chilled back down to 33 degrees when served. The worst environmental element for beer is direct sunlight, especially on clear or green bottles. The effect of sunlight on brown bottles is mostly negligible. The MGD, High Life, and Rolling Rock brands, of the popular domestics, are the most temperamental when it comes to storage, just because of the bottle. The worst problem you'll probably encounter with mass market domestics is bitterness from the beer settling and separating. Pour it into a glass and the "problem" is fixed.
Microbrews are another matter, depending on the parent brewer and whether it is a national (Sam Adams) or a regional (Great Lakes Brewing). Nationally shipped micros are typically pastuerized; they keep their "micro" roots in name only. For example, the Pete's Wicked that is on your store shelf is effectively a mass market domestic, as it is brewed at the Stroh plant. Leinenkugel's national retail product is brewed by Miller.
The regional microbrews are the only ones you should really be concerned about, and it's not as if you're going to often buy those more than six at a time. It's more an issue of how your retailer stores your preferred regional micro, not what you do with it. You do not want a regional micro exposed to varying temps. It'll separate and the yeast will begin fermenting over again, resulting in a nasty beer with slimy strands suspended in it.
FWIW, tobacco products are far more sensitive to environmental storage than alcohol, particularly if you cannot control humidity.
Shit. I've got myself all worked up now. I need to go home and have a Blue Moon Belgian White and an Opus X.