12. World War Z (June 21): With the success of AMC's The Walking Dead and February's Warm Bodies ($66.2 million), it's safe to say that zombies are very popular right now. World War Z is the first big-budget aspiring blockbuster featuring the creatures, though casual audiences may have a tough time associating the movie's fast-moving swarms of CGI zombies with the slow-moving ones they are used to. With star Brad Pitt and what's sure to be a hefty marketing effort from Paramount, World War Z will likely do fine, but opening right after Man of Steel is going to keep this down. (Domestic: $135 million, Foreign: $285 million)
13. Epic (May 24): Action-oriented animated movies (as opposed to comedic ones) aren't historically all that successful, and Epic's story calls to mind notorious animated bomb The Ant Bully ($28.1 million). Still, from a scheduling perspective, Epic is in great shape: Memorial Day weekend is typically a good time to release an animated movie, and its closest competition (Monsters University) comes out four weeks later. (Domestic: $130 million, Foreign: $245 million)
14. The Wolverine (July 26): The most popular character from the X-Men franchise makes his second solo appearance this Summer; the first outing, X-Men Origin: Wolverine earned a very good $179.9 million in 2009 but was for the most part met with tepid reactions. In an effort to win back some people, The Wolverine takes him to Japan in the big-screen adaptation of one of the character's most-popular comic book arcs. While that's going to go a long way with intense fanboys, general audiences aren't likely to care much, and lower domestic grosses seem inevitable. (Domestic: $125 million, Foreign: $250 million)
15. Elysium (Aug. 9): In 2009, District 9 was a surprise hit both commercially and critically: the low-budget sci-fi flick earned $115.6 million at the domestic box office and snagged a Best Picture nomination at the Oscars. Director Neil Blomkamp's follow-up Elysium looks like a similarly strong outing, and has the added benefit of Matt Damon in his tough-guy wheelhouse. There is some risk that following Oblivion, After Earth and Pacific Rim, audiences will be burnt out on futuristic sci-fi by August, but Elysium should be able to do solid business regardless. (Domestic: $120 million, Foreign: $155 million)
16 (tie). The Smurfs 2 (July 31): The first Smurfs movie earned a very good $142.6 million at the domestic box office in 2011—the sequel was greenlit mainly because of the foreign grosses, though, which wound up a staggering $421 million. Domestically, at least, the movie benefited from incredibly weak competition for family audiences that Summer: Kung Fu Panda 2 and Cars 2 both underperformed a bit, and were basically gone from theaters by the time The Smurfs opened at the end of July. The competition is much more intense this year, though, and as a result The Smurfs 2 is likely in line for a noticeabledecline. (Domestic: $115 million, Foreign: $460 million)
16 (tie). Turbo (July 19): Even though Rise of the Guardians barely made it, DreamWorks Animation has now had 13-straight movies earn over $100 million at the domestic box office. Turbo won't reverse that trend, though coming on the heels of three other major animated movies this Summer, it's likely that family audiences are going to be exhausted by this point. It also doesn't help that the movie feels a bit derivative of Pixar's Cars; all in, this is likely going to be a lesser outing from DreamWorks Animation. (Domestic: $115 million, Foreign: $205 million)
18. Grown Ups 2 (July 12): The first Grown Ups is one of Adam Sandler's biggest hits ever with $162 million. Since then, though, Sandler's brand appears to have taken a bit of a hit: Jack and Jill underwhelmed with $74.2 million, while That's My Boy flopped last Summer with $36.9 million. Also, as is inherent with many sequels, Grown Ups 2 just doesn't look as fresh or original as the first movie, and a lower gross should follow. (Domestic: $110 million, Foreign: $125 million)
19. After Earth (May 31): Based on star power alone, After Earth ought to be a hit: Will and Jaden Smith's first movie together, The Pursuit of Happyness, earned $163.6 million, and their last two individual movies (MIB 3 and The Karate Kid) each grossed over $175 million. Unfortunately, it's opening in the shadow of what should be the biggest Memorial Day weekend ever, and it looks like it could be too intense for children and too cartoonish for adults. The big money for this one is overseas, where the elder Smith's movies consistently gross over $300 million. (Domestic: $105 million, Foreign: $310 million)
20 (tie). The Great Gatsby (May 10): Opening in between Iron Man 3 and Star Trek Into Darkness, it could be tough for The Great Gatsby to get much attention. However, its eye-catching previews and fantastic cast—including Leonardo DiCaprio in a role that he seems born to play—do appear to be drawing some buzz recently, and it's likely that this is a modest early Summer hit with adults. (Domestic Forecast: $100 million, Foreign: $150 million)
20 (tie). 2 Guns (August 2): Late Summer is a good time to release an adult-oriented action movie, and Universal seems to have a great option in 2 Guns. The movie finds Denzel Washington and Mark Wahlberg as undercover federal agents forced to team up, and the previews suggest the two have an easy, appealing chemistry. It won't be a huge hit, but a $100 million finish wouldn't be surprising at all, especially considering Washington's recent track record. (Domestic: $100 million, Foreign: $95 million)
Other Noteworthy Titles
There are a handful of major releases that didn't make this list. Here's a breakdown of those titles, with a quick explanation for why they were left off.
The Internship (June 6): A reteaming of Wedding Crashers duo Vince Vaughn and Owen Wilson should be a slam-dunk, but The Internship's odd trailers give off the impression this movie should have come out in 2007, not 2013.
This is the End (June 13): Previews for This is the End deliver a lot of laughs, but the notion of stars playing themselves is something that probably won't connect outside of major cities.
R.I.P.D. (July 19): If there's one Summer 2013 movie that's likely to take the Jonah Hex awards (ill-advised, low-grossing comic book adaptation), it has to be R.I.P.D.
Red 2 (July 19): 2010's Red was a surprise hit with $90.4 million; while the sequel does add a few interesting cast members (Catherine Zeta-Jones, Anthony Hopkins), it feels like the premise itself has already worn out its welcome.
300: Rise of An Empire (Aug. 2): The original 300 earned an incredible $210.6 million in 2007, which made a follow-up seem very logical. However, that movie had a very definitive ending, and without director Zack Snyder or star Gerard Butler, audiences are likely going to treat this as nothing but a knock-off.
Percy Jackson: Sea of Monsters (Aug. 7): The first Percy movie was a solid performer with $88.8 million at the domestic box office—the sequel, though, appears designed specifically to build on the $138 million foreign haul, and the best-case scenario is that domestic winds up about even.
Planes (Aug. 9): This Cars spin-off was originally supposed to be direct-to-video, but early this year Disney decided on a theatrical release. Unfortunately, August is historically a dead zone for animated movies, and it doesn't help that so many major animated releases are coming before it this Summer.
We're the Millers (Aug. 9): Without a ton of comedy competition and with Horrible Bosses stars Jennifer Aniston and Jason Sudeikis, this could wind up a surprise hit—unfortunately, there's almost no material available for this title right now, so it's going to stay off the main list.
Kick-Ass 2 (Aug. 16): Riding a wave of hype, the first movie only wound up with $48.1 million; even coming off strong home video business, it's unlikely that this sequel drastically outgrosses its predecessor.
One Direction: This is Us (Aug. 30): The One Direction 3D concert movie could be a minor late Summer hit, but it's unlikely it matches Justin Bieber: Never Say Never ($73 million).
This kind of a thread pops up every year.