More than making a bold stance, I decide instead to bring facts. Let’s get definitive. Below are the number of elements that support the theory, as well as some support from involved individuals. They key in assessing things is how many Christmas elements are not just present (pun intended) but actually are in service to the plot.

The film is centered on John McClane, a New York police officer traveling to California. He and his wife have separated and she has taken an executive position with a corporation in Los Angeles. Cue the glad tidings.

• On board the plane John is seen traveling with a teddy bear, a Christmas gift for his daughter.
• John arrives at the airport and he meets his young limo driver, who compliments his bear. The driver is named ARGYLE, after the traditional Christmas gift of socks.
• Soon after John’s wife is on the phone with their daughter, who asks if her father will be there for Christmas. She answers with, “We’ll see what Mommy and Santa can do.”
• The bulk of the film takes place on one location — on Christmas Eve.
• John goes to his wife’s workplace, where they are staging the iconic Christmas party. This party is crucial to the plans of the terrorists accessing the building.
• John’s wife’s name? HOLLY.
• Ellis is the office negotiator, and also a cocky stooge. He is seen at Holly’s desk doing a line of cocaine – also known as “snow”.
• After taking control of Nakatomi Plaza, the building is surrounded by police, who attempt to get inside. As they do Theo, the tech expert with the terrorists, is watching their action on the monitors, and reports to the team thusly: “All right, listen up guys. Twas the night before Christmas, and all through the house, not a creature was stirring, except… the four assholes coming in the rear in standard two-by-two cover formation.”
• John McClane takes out the first terrorist, and sends him down the elevator for the terrorist group to find. He is adorned thusly:

https://giphy.com/gifs/die-hard-machine-gun-ho-oMK5z1GT0B87S

• When opening the vault’s layers Theo radios in the Hans Gruber, saying that breaking through the last stage will take a miracle. Hans responds back with, “It’s Christmas, Theo. It’s the time of miracles. So be of good cheer… and call me when you hit the last lock.”
• The FBI agents demand the Utility company on scene cuts the power to an entire electrical grid. One person debates that will mean shutting off power to the bulk of the city of Los Angeles on Christmas Eve.
• When the FBI cuts the power to the building that disable the final lock on the vault, and it opens for the terrorists. Theo stands up and in awe says, “Merry Christmas!”
• At one stage the terrorists intend for the hostages to be moved by helicopter, so they guide them to the helipad on the building – in other words, Up On The Rooftop.
• In the penultimate face off with the terrorists McClane seemingly gives up, but we see a gun affixed on his back, held in place with Happy Holidays packing tape.
• As everyone is exiting the building safely following the explosion clouds of paper are falling, a metaphorical snow scene for the finale.
•  When the end credits come up the soundtrack starts playing the Yuletide classic, ”Let It Snow”.

These are merely touchstone moments I am pointing out. But my testimony does not hold sway without a certain level of confirmation. So, in an effort to avoid being classified as a baseless whistleblower with only second-hand information, I can actually offer up corroborating witness testimony.

First, the general public displays a vested and measurable interest in the film, that spikes in December. It is streamed heavily this time of year, while also making cable television schedules. This trend is similar to other widely accepted Christmas titles.

The film was adapted by two screenwriters from the novel “Nothing Lasts Forever”, written by Roderick Thorpe. Steven E. de Souza was one of those who worked on the screenplay and he was bidden in 2017 to weigh in on the issue by Jake Tapper. After some lighthearted exchanges, a few days later the writer offered up a helpful chart that displayed his contention on the nature of this film.

For anyone unconvinced #DieHardIsAChristmasMovie, here is a handy chart pic.twitter.com/FhkzPIG0ms

— Steven E. de Souza (@StevenEdeSouza) December 27, 2017

Additionally, de Souza adds that during the production there was mention of the film being established as a holiday favorite. Producer Joel Silver was on set one day and he remarked that the film was poised to become a yearly holiday tradition.

“While we were shooting the movie, producer Joel Silver predicted it would play perennially on television during Christmas,” recalled de Souza, who co-wrote the script with Jeb Stuart, based on a novel by Roderick Thorp. ”Seeing all the Christmas decorations, it hit me how he was probably right,” de Souza said.

That is as strong an indicator as you need — prior to its release the people behind the film’s production saw it as holiday fare. So go forth, and feel free to indulge deeply in the festivity while watching John McClane heroically save the holiday.

And for those who disputed this as a holiday classic, all that can be said is one thing — “Welcome to the party, Pal!”