There used to be three things you could count on in autumn: new TV shows, thicker magazines and a woeful lack of decent mainstream films.

This year, however, the September-October span is shaping up as much more than the usual post-summer cool-down.In place of bankrupt offerings of recent vintage like “The Watcher” or “Ballistic: Ecks vs. Sever,” brawnier projects are being marshaled for broad audiences during the ’03 season. So much so, in fact, that some weekends are looking uncomfortably over-stuffed.

Sept. 12 features four wide releases: “Matchstick Men,” “Once Upon a Time in Mexico,” “Cabin Fever” and “Cold Creek Manor.” Sept. 26 brings forth “Under the Tuscan Sun,” “Duplex” and “The Rundown.”

Those battlegrounds pale next to those of Oct. 10 and 24.

The Oct. 10 Columbus Day weekend is a free-for-all with the first “Kill Bill,” “Good Boy!” “Intolerable Cruelty,” “House of the Dead” and “Mystic River” — thus pitting such filmmakers as Quentin Tarantino, the Coen Brothers and Clint Eastwood.

Oct. 24 marks the bows of “Scary Movie 3,” “Beyond Borders,” “In the Cut,” “Lil’ Pimp,” “Gothika” and “Who’s Your Daddy?”

Other potential October biggies include “Runaway Jury,” “Out of Time,” “School of Rock” and “Texas Chainsaw Massacre.”

That bulging roster does not even account for the myriad limited releases that will be cranking up their awards pitches as they compete for screens throughout the fall. The numbers suggest that 2003 domestic B.O., which still trails the 2002 pace, could use the fourth quarter to erase the deficit — as well as unpleasant memories of a mixed-bag summer.

“Everyone is now not shy of the interim between the summer and the holiday season,” notes Nikki Rocco, distrib chief at Universal. “The feeling is that if there is good enough product, people will go see it.”

Why the boldness all of a sudden? There are several reasons:

  • Summer battle fatigue

Having lived through the carnage of May-August, filmmakers and marketers are eager for a respite where they don’t feel at risk of getting pulverized by summer tentpole rivals. The modern prototype is “Meet the Parents,” a broad-appeal comedy that scored in mid-October basically because it was a broad-appeal comedy in mid-October.

Though Rocco emphasizes how far off the date is, it is nonetheless intriguing that U chose Oct. 7 of 2005 — the same weekend “Parents” had — for its long-promised CGI pic “Curious George.”

  • Holidays come early

Increasingly valuable real estate around Veterans Day and a fear of getting lost in the post-Thanksgiving shuffle has led to a November slate full of potent titles like “Matrix: Revolutions” and “Master and Commander.” Statistically, these are fall releases, but they play more like event pics once reserved for the holiday season.

  • The people have spoken

Just as the TV networks finally realized they could do business in the summer, film studios may finally be coming around to the simple notion that crowds will turn up for quality fall fare. The all-important under-25 crowd may be back in school, but auds of all ages can, and increasingly do, materialize on weekends.

Last year’s surprising bounty helps confirm that notion. Though the lineup seemed lightweight at first glance, “Barbershop,” “Sweet Home Alabama,” “The Ring” and “Jackass: The Movie” all delivered stronger-than-expected grosses in September and October.

Midbudget dramas are the pics that tend to fill fall’s Bermuda Triangle. Pics like “Almost Famous,” “The Truth About Charlie,” “Pay It Forward” and “Riding in Cars with Boys” epitomize financial pain because they skew distinctly to adults and therefore have less upside in ancillaries if they fail theatrically.

(Dave McNary contributed to this report.)