Twentieth Century Fox invited a group of scientists to preview this movie, to test their reactions to the "science" used in it. 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 this movie, but N.A.S.A. stated that the events in this movie were too ridiculous actually to occur, and 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all of its employees stating that they were not allowed to comment on the likelihood of the events portrayed, but later rescinded this restriction.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.

The river crossing scene was actually filmed on the U.S.-Mexico border, and the extras really were crossing the Rio Grande into Mexico.

In 2008, Yahoo! Movies listed this movie as one of the Top 10 Scientifically Inaccurate Movies.

There were 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.

This movie 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?"

South Park (1997) creators Trey Parker and Matt Stone managed to get their hands on a copy of this movie's script during its pre-production. The two planned to secretly shoot the same movie 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 movie would never get released.

The breath appearing out of the actors' and actresses' mouths in the cold scenes was all put in afterwards with CGI. This proved to be a more practical way of doing it, rather than freezing the set.

Writer/producer/director Roland Emmerich estimated that at least 1,000 digital artists worked on this movie.

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 movie.

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.

According to Roland Emmerich, Emmy Rossum gave Jake Gyllenhaal a deep French kiss during their first read together.

Emmy Rossum was only fifteen years old when she auditioned for this movie.

During the party after the first round, Sam's "Hello My Name Is..." sticker bears the name "Yoda".

The opening shot of the ice shelf is completely CGI, and lasts just over two and a half minutes.

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 this movie 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 $200,000 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 off-set by the planting of trees, and investments in renewable energy.

Roland Emmerich started writing the screenplay while he was filming The Patriot (2000). He stopped after 9/11, thinking a disaster movie inappropriate after such a cataclysmic real-life event.

The movie had a subplot involving Rick Hoffman that was mostly cut out of the movie, 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.

Has the biggest opening weekend gross for a movie that did not reach number one at the U.S. box-office.

The highest grossing movie to be made in Canada.

The flat image of the Earth surface used during the presentation is available to the public, and can be downloaded from http://earthobservatory.nasa.gov

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."

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 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 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 U.K. blizzard footage is from a January 2002 report.

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.

Nine special effects houses worked on this movie for over a year.

During the filming of the tsunami scene, Jake Gyllenhaal needed to use the restroom very badly, so he went in the water tank.

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.

A storm swell 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 storm swell was two hundred eighty feet (eighty-five meters) high.

During the point where the people of New York City are walking on the ice, the police officer's vest is half-covered, so it reads only "ice".

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.

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.

Lindsay Lohan was in talks to play Laura, and came close to signing a contract to appear in the movie. She had to back out at the last minute due to major scheduling conflicts.

Promoted with Countdown-to-Doomsday style clocks in theaters.

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 (Adrian Lester's) first appearance is when he is saying goodbye to his wife Jeanette (Anne Day-Jones), who is travelling to Spain; Terry Rapson (Sir 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.

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).

In the movie, several tornadoes devastate Los Angeles' downtown and the surrounding area. Although it's not 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).

Harald Kloser's score for this movie landed him the gig for Alien vs. Predator (2004).

Towards the end of the movie, when the President is giving his "thanking the third-world countries" speech, the channel he is giving the speech on is The Weather Channel.

The idea that Nietschze and his sister had an incestuous relationship is based on "My Sister and I", an autobiography widely believed to be a forgery by Oscar Levy.

Sam attends Woodmont Public School in Arlington, Virginia. The name is real, but the building is empty, used primarily for field space, voting, and community meetings.

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.

The whole wolves attacking the ship sequence took only five days to film.

The tornado destruction of Los Angeles was the final scene to win the Best Action Sequence award for MTV's Movie Awards before that award was discontinued.

Reportedly, Perry King was cast as the U.S. President as an inside joke, due to his strong resemblance to former U.S. Vice President Al Gore.

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.

On the bookshelf behind Jack's bed are the novels "Sacred" and "Gone, Baby, Gone" by Dennis Lehane, who also wrote "Mystic River", which featured Emmy Rossum in its movie adaptation.

Kenneth Welsh appeared in Category 7: The End of the World (2005), another weather disaster movie. The movie featured Dennis Quaid's brother Randy. Both movies had a scene where a tidal wave hits the Statue of Liberty.

The archaic English word "overmorrow" means "the day after tomorrow", or the German equivalent "├╝bermorgen". 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.

Some movie posters featured a fallen Statue of Liberty which was a design concept which has also been used for not just this movie, but for others. The titles are Planet of the Apes (1968), Escape from New York (1981), and The Jupiter Menace (1982).

In the tornado sequence, the janitor is listening to a soccer 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 soccer matches.

Kenneth Welsh played U.S. President Harry S. Truman in Hiroshima (1995).

Kenneth Welsh (U.S. Vice President), Mimi Kuzyk, and Chuck Shamata were born in Canada.

When Sam and Laura get the question right at the decathalon, the next question asked was "In what year did Louis Quatorze (XIV in French) ascend to the throne of France?" The correct answer would have been 1643. Louis XIV reigned for seventy-two years on the throne of France.

Dennis Quaid and Tamlyn Tomita appeared in Come See the Paradise (1990).

Kenneth Welsh and Chuck Shamata appeared in Death Wish V: The Face of Death (1994).

The cover art of the original DVD and Blu-ray cases of this movie showed the original poster showing a frozen Statue of Liberty buried in snow and ice up to her nose. When the DVD and Blu-ray were re-released in 2015, the cover art of the cases was changed to show the Brooklyn Bridge being hit by a storm surge.

The tidal wave that struck Manhattan would have demolished the skyscrapers that it hit & it would have caused much greater flooding than is shown in the film.

The eye of the storm is meant to draw supercooled air from the upper troposphere, & is stated for being the reason people are instantly frozen. The air temperature in the upper troposphere is around -57C / -71F, even at the most extreme it does not fall below -80C / -112F, at that temperature people do not instantly freeze & nor do buildings. Oymyakon, in Siberian Russia holds the record for the coldest permanently inhabited place on Earth, when it dropped to -71.6C / -97F, yet nobody was killed by that cold snap. In order to instantly freeze you would need a medium that has great heat transference, and air doesn't.

Humans can only survive for around 3 days without water, yet any existing water in the library would have quickly frozen in the cold temperature & there does not appear to be any method of melting the snow outside, using the fire in the library, to create more water.

Roland Emmerich directed a similar disaster movie five years later, 2012 (2009).

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).

Mark Gordon: The British helocopter pilot who is instantly frozen after the crash.