Director Roland Emmerich read "The Coming Global Superstorm," a non-fiction novel by Art Bell and Whitley Strieber, before he began writing for this film. 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.
While speaking to fans in Denver, director 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.
Roland Emmerich, out of his own pocket, paid $200,000 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.
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 US 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 USA.
Casting Kenneth Welsh as the Vice President was controversial due to his physical resemblance to US Vice-President Dick Cheney, but Roland Emmerich insisted on it for that very reason, likely to highlight the Bush/Cheney administration's opposition to the Kyoto Protocol for reducing greenhouse gas emissions.
Before the film was released, NASA sent a memo out to all of its employees stating that they were not allowed to comment on the likelihood of the events portrayed in this movie, but later rescinded the restriction.
The consultation by NASA scientists was requested before the filming of the movie, but NASA stated that the events in the film were too ridiculous to actually occur, and hence denied the request.
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.
The footage shown on TV of the blizzard storm in the UK is taken from an actual news report in January 2002.
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.
After seeing Jake Gyllenhaal in October Sky (1999), director Roland Emmerich wanted to work with him. When he decided to change the character of Sam to an older person, he immediately asked, "Can Jake Gyllenhaal play a 17-year-old?"
During the filming of the tsunami scene, Jake Gyllenhaal needed to use the restroom very badly, so he went in the water tank.
The opening weekend gross of this film, along with the second weekend gross of Shrek 2 (2004), represents the most money ever earned in a single weekend in movie history.
When Sam calls his father to tell him the sewer has backed up into the school, Kirsten Dunst is standing at his elbow, her sweater pulled up over her nose and mouth. Dunst was on set visiting Jake Gyllenhaal, whom she was dating at the time.
The footage of the hurricane is of Hurricane Iniki, which hit Hawaii in 1992. It was shot by Emmerich's assistant Aaron Boyd, who renamed the storm "Hurricane Noelani" after his Hawaiian wife.
In the scene of the British helicopters crashing, Producer Mark Gordon plays the pilot being instantly frozen.
In the scene in Tokyo after the man drops his phone in the hailstorm, the voice on the other end is saying "Taka? Daijoubu? Taka?" In Japanese, "daijoubu" means "Are you ok?"
The opening shot of the ice shelf is completely CG and lasts just over 2 1/2 minutes.
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
The Mexico-United States "bridge" shown is really just an overpass in El Paso, Texas. It was chosen because it overlooked Mexico in a dramatic way. The real bridges in El Paso don't look like that and don't even say "Mexico" or "United States of America" on their respective sides. Also, security is much stricter with fences and Border Patrol agents.
During the point where the people of New York are walking on the frozen ice, the police officer's vest is half-covered, so it reads only "ice."
The river crossing scene was actually filmed on the US-Mexico border, and the extras really were crossing the Rio Grande into Mexico.