Investors digested word today that Wal-Mart (NYSE:WMT) has lowered its sales forecast for August, with the possibility that same-store sales may come in flat to up 2%. Just last week, the behemoth retailer had called for a 2% to 4% increase in same-store sales for the month. Since then, investors have surely been thinking the annual back-to-school shopping frenzy and Hurricane Charley would be sales boosters.

When it comes to Hurricane Charley, sure, many people likely rushed to their local Wal-Marts for everything from bottled water to candles to batteries. Apparently that wasn't enough to offset the fact that the retailer had to close 75 stores for a period in the affected areas, while a total of 200 stores in some way felt the hurricane's wrath.

Meanwhile, back-to-school sales apparently are not materializing as hoped. One might wonder how much of that has to do with the fact that the long Labor Day weekend heralding the end of summer has shifted this year, to occur in September instead of August.

It wasn't too terribly long ago that I reported on Wal-Mart being one of the discounters that doesn't quit. At that time, Wal-Mart felt "optimistic" about the consumer and the back-to-school season, despite leeriness over high gas prices and such factors that might depress shoppers. Rival Target (NYSE:TGT) also had upbeat news that belied this summer's June ennui.

Despite it all, Foolish colleague Steven Mallas made excellent points recently when he explored Wal-Mart's same-store sales, which already weren't as robust as some might have hoped. However, he pointed to the high same-store sales figures last year, which included the benefits of child-care tax credits. He also indicated that Wal-Mart investors shouldn't get caught up in the weekly and monthly machinations of the retailer unless a definite trend begins to form.

The same goes here. Despite the possibility of a slow back-to-school season, it still behooves investors to watch the big picture and avoid pessimism over short-term movements. What's perhaps more interesting here, of course, is the perceived connection between Wal-Mart's sales and consumer confidence, another example that it has been an unpredictable summer for retail.

Is Wal-Mart slowing down? Do you just ignore such ups and downs? Join up with some other Foolish investors to talk about the issues that face the company on the Wal-Mart discussion board.

Alyce Lomax does not own shares of any of the companies mentioned.