Finding Dory movie
“Finding Dory” found almost no competition last weekend, setting an opening weekend box office record for an animated movie. Disney/Pixar

LOS ANGELES — Disney’s “Finding Dory,” which just had the biggest-ever opening weekend for an animated film, proved that the early summer box-office slump was only a false alarm. Americans still love beating the summer heat inside an air-conditioned multiplex. It’s just that to American audiences, it seemed like other studios took the beginning of the summer off.

“Finding Dory,” the long-awaited sequel to 2003’s “Finding Nemo” from Disney’s Pixar imprint, rolled to a $136 million opening weekend as Americans headed back to the theaters after taking the last few weeks off. The 13-year gap between movies seemed to only ramp up the anticipation, and the movie’s sterling reviews helped, including a 95 percent score on film critic aggregator Rotten Tomatoes. So did its favorable Father’s Day weekend release date, as well as an extreme heat wave across much of the Southwest that made a matinee seem like a perfect idea.

But a bigger factor could have been the lack of competition for those younger viewers. Summer movie season is usually packed with big-budget hits, but “Finding Dory’s” mid-June release date came amid an unusual lack of competition. That wasn’t deliberate. Rather, you might say it was a bit of serendipity built on the misfortune of other, less successful sequels. Paramount, for instance, didn’t expect its sequel to “Teenage Mutant Ninja Turtles” to bring in just $72 million since its June 3 release date, but the failure of other movies to draw crowds cleared the waters for “Finding Dory.”

The “Finding Dory” world premiere was held at El Capitan Theater in Los Angeles, June 8, 2016. Reuters/Mario Anzuoni

Even with “Dory’s” total, the top 12 films this weekend delivered just $226 million, after making up $144 million and $128 million the two weeks before. To compare, during last Father’s Day weekend, “Jurassic World” topped the box office with $107 million in its second week on its way to more than $652 million in total. “Inside Out” was second with a $90 million debut. Six of the top 10 films that weekend eventually earned more than $150 million at the domestic box office — three cleared $350 million — and the top 12 movies accounted for $242 million, after totaling $267 million and $126 million over the first two weekends in June.

And while “Finding Dory” was a sequel — like so many other big-budget Hollywood movies lately — it rose where others sank. Unlike the quick turnarounds in Fox’s “X-Men” and Paramount’s “Teenage Mutant Ninja Turtles” franchises, both of which had movies that disappointed this summer, “Finding Nemo” came out long enough ago to foster real nostalgia, but recent enough to remain relevant. On the other hand, Fox’s “Independence Day: Resurgence,” which will be released this weekend, a full 20 years after the first installment, may have waited too long. But plenty of people who enjoyed “Nemo” as kids brought their own children to “Finding Dory,” and a substantial adult audience delivered strong results from later showtimes, as well.

Disney isn’t totally immune to missteps in sequeling — “Alice Through the Looking Glass” flopped last month under bad reviews after its predecessor, “Alice in Wonderland,” made more than $1 billion worldwide in 2010. But for the most part, Disney has succeeded where others have failed. The studio’s string of hits and pipeline full of bankable franchises, from “Star Wars” to the Marvel Cinematic Universe, should allow it to be more patient, and not rush movies through to hit quarterly numbers, resulting in better quality.

More likely, Disney’s magic is simpler than that — it made movies that people liked, regardless of what came before or after them. Movie fans around the world had been begging for new “Star Wars” and “Finding Nemo” films for years, and the fact that critics had effusive praise moved them from “interested to see” to “have to see.” In contrast, Paramount execs were the only ones really craving a new “Teenage Mutant Ninja Turtles” movie, and it showed.

One seemingly down note for “Finding Dory” was its relatively slow start in China, where it opened with about $18 million in a country that’s gone crazy for other animated flicks this year. “Zootopia” is the highest-grossing animated and Disney movie of all time in China, finishing with nearly $236 million there.

But despite the Mouse House’s golden touch with its other brands, from Walt Disney Animation to the Marvel Cinematic Universe, Pixar films have struggled there. With about $34 million, 2013’s “Monsters University” is Pixar’s highest-grossing movie in China. For whatever reason, Pixar’s messaging and style hasn’t seemed to connect with Chinese audiences, and last year’s “Inside Out” made a meager $16 million in China after a long release delay made high-quality pirated copies of it widely available.

However, industry analyst Jonathan Papish of China Film Insider believes the “irresistibly adorable” characters and less complicated plot should make “Finding Dory” easily the biggest-ever Pixar movie in China, even if it won’t come close to “Zootopia” territory. And with little competition for the American youth audience until Disney’s “The BFG” and Universal’s “The Secret Life of Pets,” “Dory” has a real chance to set more records at home — albeit in a watered-down field.