The film was originally scripted with Sam and his friends as eleven-year-olds, but Writer and Director Roland Emmerich changed them to high school students for Jake Gyllenhaal, who Emmerich had seen in October Sky (1999). Emmerich asked "Can Jake Gyllenhaal play a seventeen-year-old?"
20th Century Fox invited a group of scientists to preview the film, to test their reactions to the science used in the film. None of the scientists were impressed with what they saw, although most conceded that the movie was enjoyable nonsense.
The consultation by N.A.S.A. scientists was requested before the filming of the movie, but N.A.S.A. stated that the events in the film were too ridiculous actually to occur, and hence denied the request. N.A.S.A. sent a memo out to all of its employees stating that they were not allowed to comment on the likelihood of the events portrayed, but later rescinded this restriction.
The U.S. Army loaned several UH-60 Blackhawk helicopters for the rescue scene at the end, prompting the Canadian authorities to reassure the people of Montreal that they weren't being invaded by the U.S.
There was some doubts among the production team about having a major disaster hit New York City, especially after 9/11. That sensitivity did not appear to be shared by New Yorkers. Whenever it played in the Big Apple, audiences whooped with delight when the city gets hit by an enormous tidal wave.
South Park (1997) Creators Trey Parker and Matt Stone managed to get their hands on a copy of this film's script during its pre-production. The two planned to secretly shoot the same film with puppets instead of actors, word for word, and release it on the same day. The duo abandoned these plans after their lawyer convinced them that such a film would never get released.
Roland Emmerich confided that the Statue of Liberty would be turned over by the force of the massive amount of water flowing around it, but said he wanted to create a symbol of American values that stood up to the forces.
The Red Cross put up several stands at theaters in the U.S. featuring pamphlets with information on what to do to keep safe during tornados, floods, and blizzards for concerned people who had just viewed the film.
While speaking to fans in Denver, Roland Emmerich said he became interested in doing a movie involving weather, while shooting The Patriot (2000). He said his whole day revolved around what the weather forecast was in order to shoot the outdoor scenes and that he really just wanted to control the weather himself. "The Coming Global Superstorm", a non-fiction novel by Art Bell and Whitley Strieber, was used for reference. Emmerich concedes that while the events portrayed in the film are indeed possible, the time frame over which they take place was implausibly short, and tailored for sheer entertainment value. In keeping with the movie's ecological theme, Emmerich paid two hundred thousand dollars from his own pocket to make the production "carbon-neutral", the first of its kind in Hollywood, all carbon dioxide emitted by the production was offset by the planting of trees, and investments in renewable energy.
The casting of Kenneth Welsh as the Vice President was controversial, due to his physical resemblance to Vice President Dick Cheney. However, Roland Emmerich insisted on it for that very reason, admitting that the characters of the President and Vice President were intended to be criticism of the Bush and Cheney administration's opposition to the Kyoto Protocol for reducing greenhouse gas emissions.
The movie had a subplot involving Rick Hoffman that was mostly cut out of the film, where Hoffman and his two friends were unethical businessmen who were working on an illegal securities trading plan with a Japanese colleague. The Japanese man is still shown being struck and killed by mega-hail falling during the ice storm siege, but footage of him talking to Hoffman's character about how they needed to steal money to avoid going to prison was edited out. This explains why Hoffman and his friends are introduced during the massive wave destruction in New York City and appear to be unlikable characters before they're demolished by the water (and their bus is later crushed by the freighter ship), since they had unused footage establishing them as bad guys.
Two library-bound survivors ask whether they should burn the works of Friedrich Nietzsche, whose "The Antichrist" states in its preface: "Only the day after tomorrow belongs to me. Some are born posthumously." Part of this line provided this movie's title.
DIRECTOR TRADEMARK (Roland Emmerich): (reflections): When the Los Angeles weather forecaster looks out the window of the forecast center, you can see the reflection of the tornado approaching. This same technique is also visible in 2012 (2009) when the pyroclastic cloud is seen in the reflection of the glass door as it approaches the airport in Las Vegas, Nevada.
The footage of the plane that crashed in the Midwest before the FAA's flight ban, is actually a stock photo of a January 1990 Avianca Airlines crash on Long Island. The hurricane footage is of Hurricane Iniki (1992) in Hawaii. It was shot by Roland Emmerich's assistant Aaron Boyd, who renamed the storm "Hurricane Noelani" after his Hawaiian wife. The UK blizzard footage is from a January 2002 report.
When the camera pulls away from the Earth after the astronaut exclaims "the air is so clear" the image of the Earth is a modified version of the "Blue Marble" picture created by Robert Simmon. The Blue Marble picture is comprised of thousands of satellite photos, and some of the clouds are duplicated. The Apple iPhone uses the Blue Marble picture as the default wallpaper.
In the first scene in the movie a portion of the Larsen B Ice Shelf in Antarctica breaks off. At the ensuing climate conference, Dr. Hall tells the Vice President of the United States that the last piece of ice-shelf to break off was the "size of Rhode Island". This is based on a factual occurrence between 2002 and 2003, when an area of the Larsen B Ice Shelf approximately the size of Rhode Island progressively collapsed.
The United States Embassy in Mexico was actually the Centro Vida/Life Center Ministries and school in El Paso, Texas. Mexico is visible from the building, which is on Glory Road near the University. The church and school have since moved. The Mexico-United States "bridge" is really an overpass in El Paso which overlooks Mexico. El Paso's real border bridges don't look like that. Security is much stricter, with fences and Border Patrol Agents. During filming, local residents were concerned about closed streets and military-style helicopters landing and flying low over residential neighborhoods.
On the two-disc Special Edition, (at twenty-six minutes and forty-nine seconds) the second commentary track says that the helicopter used to create the wind, was loaded with as much sand as possible. By making the load heavier, the helicopter would need to use more downward thrust, and hence create more wind.
On the shot that shows the front of the library, lamps are seen instead of the iconic lions. According to a New York City Public Library employee, the studio didn't want to pay the fee for filming the statues that are a trademark of the institution, and therefore only took advantage of the public area rights of filming.
Emmy Rossum accepted the role of Laura after Lindsay Lohan had to drop out due to scheduling conflicts. This is the first time that Rossum has stepped In for a role originally meant for Lohan. This happened again with Poseidon (2006).
The Manchester United player who is seen scoring, is Dutch striker Ruud van Nistelrooy. It was a friendly game against Boca Juniors of Argentina, which took place on August 10, 2002, and whose final score was Manchester United - 2, Boca Juniors - 0.
Domestically speaking, as of 2008, it has the second highest gross for a movie that did not reach number one at the U.S. box-office, behind My Big Fat Greek Wedding (2002). However, it outperformed My Big Fat Greek Wedding (2002) in the worldwide market.
In the tornado sequence, the janitor is listening to a football match in his headphones. The match he is listening to is Argentina Vs. Peru and the guy commenting the match is Victor Hugo Morales, a famous Uruguayan commentator of football matches.
The archaic English word "overmorrow" means "the day after tomorrow", or the German equivalent "übermorgen". This is a term, with which Roland Emmerich might have been familiar. The movie could have been called "Overmorrow" for a shorter title that means the same thing.
Kirsten Dunst: When Sam calls his father to tell him the sewer has backed up into the school, Dunst can be seen standing behind Sam near his elbow, her sweater pulled up over her nose and mouth (although in very poor light).
The trivia items below may give away important plot points.
A tsunami approaches New York City, hitting the Statue of Liberty's heels. The statue is three hundred five feet (ninety-three meters) high from pedestal to torch, the right arm is forty-two feet (almost thirteen meters) high, and Liberty Island is twenty-one feet (seven meters) high. That means the tsunami was two hundred eighty feet (eighty-five meters) high.
In the movie, several tornadoes devastate Los Angeles' downtown and the surrounding area. Although it's mentioned by any character, a tornado is measured by its destructive force with the Fujita's Scale. It was named after Tetsuya Fujita, who in 1971, in collaboration with Allan Pearson, created a scale to differentiate a twister according the wind speed: -F0: 60-117 km/h or 45- 72 mph (light damage). -F1: 117-181 km/h or 73-112 mph (moderate damage). -F2: 181-250 km/h or 113-157 mph (significant damage). -F3: 250-320 km/h or 158-206 mph (severe damage). -F4: 320-420 km/h or 207-260 mph (devastating damage). -F5: 420-510 km/h or 261-308 mph (incredible damage). -F6: 510-610 km/h or 309-379 mph (altough initially Fujita scale have five marks, in 1999 a tornado located in Bridge Creek-Moore, Oklahoma, devastated with a force more powerful never seen before. It was the only one F6 registered in history).
The movie establishes that the storm will affect all the Northern hemisphere, but that some countries will be free of the ice, among them Spain. Simon's first appearance (Adrian Lester) is when he is saying goodbye to his wife Jeanette (Anne Day-Jones), who is travelling to Spain; Terry Rapson (Ian Holm) expresses his wish to be in Spain, safe and sound from the storm; when Jack Hall (Dennis Quaid) explains his theories to the President, in the map of the television screen can be seen the ice in Europe stopping in France and Switzerland, leaving Spain and Italy without ice. However, when two astronauts from the International Space Station look at the Earth, they can see Spain and Italy fully covered in ice, as is the rest of the continent. This is not necessarily a contradiction, but a signal that the storm was more powerful than all of the scientists predicted.