“Kong: Skull Island” and “Logan” are powering the March box office to record numbers and serving as a potent reminder that blockbuster movies aren’t exclusively reserved for the summer. Ever since “The Hunger Games” opened to $152.5 million in 2013, studios have been pushing bigger and bigger movies earlier into the year. Last March hosted “Zootopia” and “Batman v Superman: Dawn of Justice,” an animated adventure and a comic book mashup that never would have opened before Memorial Day in years past. But their backers were rewarded for their calendar flexibility with a combined global gross of nearly $1.9 billion.

“The movie defines the month, the month doesn’t define the movie,” said Paul Dergarabedian, senior media analyst at comScore. “March has become a monster.”

So far, 2017’s version of March is indeed a leviathan. “Logan” kicked off the month with a massive $88.4 million debut, and “Kong: Skull Island” kept cash registers humming with an impressive $61 million bow. The coming weeks will field the releases of “The Power Rangers,” a reboot of the popular children’s TV show, and “The Ghost in the Shell,” a manga adaptation with Scarlett Johansson as a spandex-suited cyborg. That’s to say nothing of “Beauty and the Beast,” a live-action Disney fantasy that is expected to debut to $120 million.

“Momentum is so important in the movie business,” said Greg Foster, CEO of Imax Entertainment. “When you have a couple of movies in a row that work, there’s a surge effect that takes place.”

Foster believes that one good moviegoing experience begets another — consumers’ appetite for big screen diversions is whetted by a fun night out at theaters and their interest is piqued when they see trailers and posters for other upcoming movies.

Whatever is motivating the boom time for multiplexes, the March box office has a good chance of matching or even eclipsing last year’s record-breaking $948.8 million in domestic ticket sales. That was led by the $255.9 million that “Zootopia” earned within the month and the $209.1 million that “Batman v Superman” made during the period.

Through Sunday, ticket sales have already reached $436.5 million with more than half of the month left to go. That means that this March could be the first billion dollar grosser in history.

“This feels like early summer,” said Jeff Bock, a box office analyst with Exhibitor Relations. “To have a spring month capable of supporting this many big blockbusters is pretty impressive…it’s going to change the release paradigm.”

In many respects, the paradigm has already shattered. Gone are the days where Memorial Day signaled the true start of summer movie season. Of course, the lines have been blurring for awhile. In 1996, Warner Bros. helped usher in a more capacious definition of summer by debuting “Twister” on May 10 — a decision that flew in the face of conventional wisdom that suggested that it was too early in the year for moviegoers to surrender themselves to lighter, airier crowd-pleasers. It was Universal that further extended the boundaries of popcorn season by opting to release several “Fast and Furious” sequels in the month of April, starting in 2009. Vin Diesel and company will be back to their drag racing ways on April 14 when “The Fate of the Furious” opens in theaters.

There are business reasons the pace of change needs to accelerate. Studios are moving away from the types of mid-budget comedies and dramas that used to routinely pop up in the spring and fall. They’re making fewer movies, but placing bigger bets. The mania now is for pricey event films featuring King Kong or Wolverine, that can inspire a range of consumer products from toylines to video games. If these films are only released between May and June, they will cannibalize one another, creating an epic battle every weekend that leaves every studio badly bruised.

In this climate, it makes sense that even with a chill in the air and snow on the ground, March signals the true start of summer for the movie business.