Unless a work of fiction is in a tropical or arid setting, or in the southern hemisphere, it will always snow in winter. That's how you know it's winter. Christmas time in particular is always a Currier & Ives picture-postcard affair, hence the trope name. If characters aren't walking outside through gently falling snow, there's at least several inches on the ground.
The snow will be there to look "pretty". It does not melt or turn slushy, and is never coated with dirt or litter. It is never accompanied by freezing winds or icy rains. It can always be easily molded into snowmen or snowballs (real snow has to be warmish and melty first). The darn stuff usually isn't even cold or wet. No one ever has trouble traveling in it unless it's a plot point, and it even conveniently vanishes by the next episode. Why, it's almost as if Mother Nature herself knows it's Christmas time and has decided to act accordingly.
This is most often seen in Hollywood New England, but will likely be the case in any setting if your writers are from southern California, which is a much warmer ecosystem and Christmas means pouring rain and flash floods. What little snow they do see is likely the dry, powdery kind from ski trips to Lake Tahoe, not realizing that snow elsewhere tends to be far more wet and heavy. See also Let There Be Snow, for when this happens when it is set in a warmer climate. Strangely enough, it seldom snows during other winter holidays except maybe New Year's. Valentine's Day in particular is almost always absent of snow despite being in the middle of February. In many real-life locales, the white stuff can fly as early as Halloween and as late as Easter.
In the United Kingdom - particularly in Southern England and Wales - there is seldom snow at Christmas (2009 and 2010 were exceptions), but much of the popular mythology of an "old-fashioned" Christmas goes back to Charles Dickens, who was being nostalgic for his childhood Christmases of the early 1800s, which happened to fall during a miniature ice age (the first eight years of his life having eight white Christmases in a row... lucky bugger).
Japan is a pretty warm place, with weather resembling the East Coast of the United States from roughly Boston to Savannah, Georgia. Tokyo is at nearly the same latitude as Norfolk, Virginia and the Outer Banks of North Carolina, an area which gets snow in the winter every few years at best. For European reference, that roughly equates Southern Europe, which includes Spain, Italy, Greece and Portugal, countries which are famous for their warm weather and where it rarely snows unless it's on high altitudes note or unless you happen to live in northern Italy, where snow is actually pretty common during the winter. Thus, if it snows in an anime or manga, it'll either be in a scene set in the far northern island of Hokkaido (which has much colder weather), or under certain circumstances (such as Snow Means Love) where it has to snow for the trope to work.
One of the few places to consistently avoid this trope is Australia — even the laziest of writers would find it hard to miss that Christmas falls at the height of summer in the Southern Hemisphere, and Australia being the best-represented country of that hemisphere in Anglophone culture, Popcultural Osmosis has caught up with the fact that they do things differently there.
A traditional Christmas advertisement for Beaurepaires tyre company shown in New Zealand shows Vince Martin dressed in a Santa costume, wandering through a snowy landscape while singing "Walking in a Winter Wonderland"... pointedly ignoring the fact that because New Zealand is in the southern hemisphere, Christmas is in the middle of summer.
Played completely straight in this long-running Christmas ad for Miller High Life beer, depicting the proverbial one-horse open sleigh tooling around a picturesque, snowy countryside.
RahXephon has a weather-controlling enemy show up specifically to justify having a white Christmas. Subverted in that everyone is quite surprised by the snow and it is in fact cold, which at least one character finds desperately uncomfortable.
Defied in Girls und Panzer in the Christmas Episode of "Motto Love Love Sakusen Desu", in which the Oarai school ship goes near Australia for Christmas, with Anzu saying that one advantage of school ships is that you can go to warm places for the winter. There is snow elsewhere, though, such as at the Nishizumi house, where Maho is hosting a Christmas party with several of her teammates.
Averted in The Death of Superman, where a week after the funeral, it was Christmas, and it was raining instead. Captain Marvel commented that he wished it would snow, but Green Lantern and Batman reminded him that since they had to bury Superman the week before, the rain seemed appropriate, and no one really wanted to think about the holidays anyway.
The first Home Alone movie depended on this trope as a setup. Not that this would be terribly unrealistic for Christmas in Chicago, a city known for its occasional blizzards (white Christmas in Chicago is a bit hit-and-miss).
In the Western film The Proposition, Christmas is used quite centrally, but there is no snow, because the characters are in the Australian Outback. Emily Watson gets a bunch of cotton and pretends it's snow.
Babe has a similar issue, set as it is in New South Wales.
No one in the film version of Bridget Jones' Diary even remarks on the tooth-rottingly quaint white Christmas happening around them even though this almost never happens in Southern England. And the film ends with Bridget kissing Darcy in a prettily snow-covered street in London.
Subverted in the film White Christmas, which takes place largely at a resort hotel in Vermont suffering for business due to an unseasonably warm winter. It finally snows at the end of the movie, which takes place on Christmas Eve.
The first two Die Hard films take place at Christmas. It only snows in the second film, outside the District of Columbia, though; the original is set in Los Angeles. (With a few exceptions, the DC area usually gets snow in late winter, if at all, not in December, and huge snowstorms arerare.)
A Christmas Story has this, but it's entirely justified: The story is set in northwestern Indiananote Jean Shepherd was from Hammond, which is bordered by just enough of Lake Michigan to be hammered by lake-effect snow every year.
Whether or not there will actually be snow for Christmas is a key plot point and gives the French film Y aura-t-il de la neige à Noël? its title.
Batman Returns is the only Batman movie in the franchise that takes place around Christmas and pretty much has snow fall upon the normally dirty streets of Gotham City.
Subverted at the beginning of the 1987 TV movie A Child's Christmas In Wales; Thomas is disappointed that it's raining on Christmas Eve. He cuts out some paper snowflakes, and his grandfather gives him a snow globe as an early Christmas present and tells stories about childhood Christmases (which involved a great deal of snow). But there's no actual snow to be seen in the present-day scenes until the very last scene of the movie, when Thomas has fallen asleep and his grandfather opens the bedroom window and catches some of the softly-falling snowflakes in his hand.
In It's a Wonderful Life, the presence or absence of falling snow on Christmas Eve is used to show whether or not George Bailey exists in a given reality, an early version of a Butterfly Effect.
The Tastes Like Diabetes little town in Edward Scissorhands starts getting snow very suddenly because Edward, who is believed dead but actually self-exiled in the castle above the town, is makng ice sculptures. One wonders where the ICE came from, though...
Played with (alongside many, many other Christmas tropes) in the Discworld novel Hogfather. In the middle of Hogswatchnight (specifically, in the alternate time-dimension used by the Hogfather to travel the Disc in a single night), the usually muddy streets of Ankh-Morpork are covered in pristine white snow — but it's acknowledged that by morning this will look more like coffee meringue.
In the novel Good Omens, by Terry Pratchett and Neil Gaiman, the unconscious shaping of his world by Adam Young means that his home town of Tadfield has the sort of weather he thinks it ought to have: "It never rained on Bonfire Night and always snowed on Christmas Eve".'
Subverted in the Dr. Seuss book Bartholomew and the Oobleck, where everything gets covered in Oobleck.
A interesting variant in Connie Willis' short story "Just Like the Ones We Used to Know" has it start pouring snow nationwide just after midnight on Christmas Eve morning... and not stop until Christmas comes. A White Christmas indeed.
Honor Harrington: Grayson usually doesn't get snow at Christmas, as they stubbornly retain their use of the Gregorian calendar even though their planetary year is nothing like Earth's. It does happen occasionally though, such as near the start of the 9th book, when the calendars just happened to coincide.
Subverted in "The Christmas Invasion". At the end, after the aliens are defeated on Christmas Day, snow starts falling amid a meteor shower. Then the Doctor mentions that it's not snow, it's ash -— the alien spaceship burning up in the atmosphere.
The M*A*S*H episode "Dear Sis" features one of the more unsubtle examples of this, when they are all in the mess tent celebrating, and then it starts snowing and they stare out the windows in amazement. For a brief moment, the camp looks pretty, but an ambulance arrives seconds later with wounded and the staff has to get back to work.
Considering they're supposed to be in Korea (despite behaving as if they're in Vietnam and the show lasting about four times as long as the actual Korean War), windows on a mess tent are all that's unusual.
Another Christmas episode, "Death Takes a Holiday", has snow start falling at the very end of the final scene...even as trees thick with green summer leaves are visible in the background. D'oh!
An episode of Third Watch's fourth season had a very heavy snowstorm hit New York (although not at Christmas), and Faith Yokas' daughter Emily was trapped in a car. The squads find her, get her to hospital, and the episode ends. The next episode begins on the next morning — and there's no sign whatsoever that the storm ever happened.
Played with in the first-season Christmas episode of Veronica Mars; to create a feeling like this, the hosts of the big party have set up a snow machine outside, along with carolers. (Of course, this being Veronica Mars, the husband then gets stabbed by the woman he cheated on his wife with, for sleeping with a third woman that night, at the big Halloween party, when he was about to try cheating on his wife with a fourth woman. Ta-daaa. Veronica, narrating, says to herself, "No, Veronica, there is no Santa Claus.")
Played with in Roswell, where Isabel at one point makes it snow in New Mexico for her brother's benefit.
Played straight in a Christmas episode of My So-Called Life; Angela and her mother stand in the falling snow outside a church.
Naturally doesn't happen in the Christmas episode of Bottom, leaving Richie to wonder, "Why doesn't it ever snow? You can't build a drizzle man, can you? Or play drizzle balls?"
Subverted in the Drake and Josh Christmas special, where at the end it looks like it's the whole "miracle snowfall in San Diego" scenario but ends up being hard cheese shredded by a maniac and his beloved wood-chipper. On a related note, this is a revision of the original plan by Drake and Josh to make snow by putting ice in the wood-chipper, which instead caused hundreds of dollars of property damage in a frozen drive-by.
The past few Christmasses in EastEnders have been white ones, even though Walford appears to be the only part of London to get any snow.
Averted in Greek. Chapter 2 begins with "spring" semester — which actually starts in late January. In Ohio. Without a flake of snow in sight. (As an aside, those of us who live in the colder parts of the United States love how it's called Spring Semester despite starting in what is usually the very worst part of winter.)
Played straight (and combined with Let There Be Snow) in a Christmas episode of The Golden Girls, in which all of their travel plans are cancelled and the four women are stuck in Miami for the holidays. Miami, Florida. Earlier in the episode, they complain about how hot it is and how they haven't seen a white Christmas in some time. But with the help of an outside observer, they rekindle their Christmas spirit and stand awestruck at the door of a diner, watching as the snow falls. They're also quite happy to see the snow, despite being held up to see their families, and also specifically mentioned that it was really light and whippy. While it hasactually snowed in Miami before, it was pretty much a freak occurrence, and it also wasn't at Christmas...
Phyllis: You know the wonderful thing about living in Minnesota? We always have a white Christmas.
Rhoda: The thing that gets me is the white Easters.
Another episode had Lou Grant deliver a rant on how he hated snow. Then he moved to Los Angeles for his spinoff show... and, during his first Christmas there, he got all nostalgic for the snows of Minneapolis.
The Christmas Special for Mighty Morphin' Power Rangers, "I'm Dreaming of a White Ranger", has the citizens of Angel Grove get a white Christmas after the Rangers save Santa Claus from Lord Zedd. Note that this is the only Christmas special the series gets for over a decade and there's no more snow in any Ranger city after that.
Highlighted in the SCTV sketch "The Fella Who Couldn't Wait for Christmas", starring a fidgety Ed Grimley:
"Oh, I can't believe it's gonna be a white Christmas; it could't be much better, I must say. Thanks, Bing! Oh, as if he had anything to do with it, but ya know, in a way I'll bet he did!"
Averted in The X-Files Christmas episodes. One takes place in San Diego and the other in Maryland. Scully notes during the one set in Maryland that the forecasters were calling for rain, and maybe a White Christmas. Not unusual for the setting; though Maryland does get snow, the winters tend to be mild and wet rather than cold and snowy.
In the Thunderbirds Christmas episode "Give or Take a Million", Brains arranges for a white Christmas on the tropical Tracy Island by setting up a snow machine.
The Eureka Christmas episode "O Little Town" has the town getting steadily warmer due to the energy buildup as it shrinks. When the energy gets released via a giant-snowflake shaped hydrogen crystal, it snows (and the crystal itself becomes a Christmas star).
The second Christmas episode "Do You See What I See", the advanced tech that goes wrong is an attempt to create holographic snow as a surprise for the kids.
James May's Man Lab: Since he's never seen one, James tries various methods to create a white Christmas, using everything from cloud seeding to liquid nitrogen. Alas, only a tiny quantity of "real snow" was produced in the end, and the crew was forced to resort to fake snow.
The Secret World of Alex Mack averts this. Paradise Valley is set in the American southwest, and lampshades this in the Christmas episode by reporting the weather is still quite hot and sunny with no snow at all. Played straighter in the series tie-in novels: Zappy Holidays has cold weather in it.
Community is set in Colorado, but filmed in Los Angeles - no snow for outdoor shots, but they get around this in the holiday episode "Comparative Religion" having the big climactic fight in the artificial snow of an outdoor 'winter wonderland' tableau.
The rarely heard intro to the Irving Berlin song for which the trope is named reveals the reason the singer is "dreaming of a white Christmas": he's in Beverly Hills.
It was also somewhat ironic at its peak of popularity in December, 1942. American troops were fighting only in North Africa (Sahara Desert) and Guadalcanal and New Guinea (in the southern tropics) at the time.
Berlin actually wrote the song while lounging by a swimming pool in Phoenix. Similarly, Bob Wells came up with the lyrics for "The Christmas Song" (Chestnuts roasting on an open fire, Jack Frost nipping at your nose, etc.) as a way of trying to "think cool" during a hot summer day in Los Angeles.
At the end of the Vietnam War, as the North Vietnamese Army approached the outskirts of Saigon, the Armed Forces Radio stations began playing Christmas songs (It was late April). Vietnam vets have said that when they heard Bing Crosby singing "White Christmas" on the radio, they knew that the end was at hand.
A popular song by the country group Alabama has the line "It's Christmas in Dixie/It's snowing in the pines." Parts of Virginia and Tennessee, which are technically in the South, do get significant snowfall because of being in or near the Appalachian mountains, but the parts most people THINK of as Dixie (Alabama, Mississippi, Georgia, South Carolina) are usually far too warm for snow.
The music video for the Dashboard Confessional song "Stolen" shows it snowing at the Hotel Del Coronado in... Coronado, CA. It NEVER snows in Coronado. Ever.
"Jingle Bells". "Jingle Bell Rock". "Sleigh Ride". "Winter Wonderland". "Let It Snow". "Baby, It's Cold Outside". "I've Got My Love to Keep Me Warm". All are secular seasonal songs with no mention of any holiday, and would be appropriate well into January (and February, and possibly even March) in many parts of the US. Yet they are rarely heard on the radio or in department stores after December 25th, and never, ever after January 1st.
Anyone who's ever worked in retail will attest this is a very good thing. Hearing nothing but Holiday music eight hours a day from after Thanksgiving to Christmas is maddening.
The Australian Christmas carol "Christmas Where The Gum Trees Grow" averts this:
Christmas where the gum trees grow There is no frost and there is no snow Christmas in Australia's hot! Cold and frosty's what it's not! When the bloom on the Jacaranda tree is here Christmas time is near!
Deliberately subverted by Greg Lake's "I Believe in Father Christmas" (Lyrics by Lake and Pete Sinfield):
They said there'd be snow at Christmas
They said there'd be peace on Earth
But instead it just kept on raining
A veil of tears for the Virgin Birth
Band Aid's "Do They Know It's Christmas?" helpfully points out that "there won't be snow in Africa this Christmas time".
Sure, there will — just on the tops of those mountains over there. Also, it's a metaphor. Kind of a silly one, but we're not going to begrudge a charity song.
Not that there aren't plenty of other examples of Western geographic ignorance in that song, including the assertion that in Africa, "nothing ever grows, no rain or rivers flow."
to be fair, they were talking about a rather nasty drought in Ethiopia at the time.
The Pet Shop Boys released a Christmas single last year appropriately and accurately called "It Doesn't Often Snow at Christmas".
Gene Autry's song "If It Doesn't Snow on Christmas" concerns itself with how Santa Claus will make his rounds in the absence of the white stuff.
Calvin and Hobbes. Every single strip set in the winter had feet of snow, enough to make snowmen giant snow beasts. Calvin apparently lived in Northern Canada.
Or in Ohio in the 60s, 70s, and early 80s (as Bill Watterson did). Yes. There really was that much snow.
Ohio, the northern part of the state in particular, gets quite a lot of snow due to the influence of Lake Erie.
Actually, there are some strips where Calvin complains bitterly about the lack of snow, and one in particular where he lights candles around his sled and then lays on it, praying to the snow demons. There's also a quote something along the lines of, "If I was in charge, we wouldn't see the ground between November and March!"
Peanuts usually featured plenty of snow in its Christmas and wintertime strips, but as with Calvin and Hobbes this was pretty well justified by the setting (generally accepted to be Minnesota, in this case).
Garfield often has a few inches of snow on the ground around Christmas time. As with the others, somewhat justified as the strip is set in central Indiana, where snow is not uncommon.
Frazz deconstructs this one here, pointing out that even Michigan doesn't always see a white Christmas, and much of the world (including Bethlehem) never does.
The Simpsons subverted this in one episode when Bart, expecting a snow day from a blizzard the previous night, walks outside to find "unseasonable warmth". Also subverted in an episode where the Simpsons travel to Australia during the winter in America. Homer, having taken a sled, is disappointed to be told by Lisa that it's actually summer in Australia.
The creators have also said that the whole origin of the "Mr. Plow" episode was because they wanted to do an episode where it was snowy but not Christmas.
There was also a Valentine's Day episode that Lisa lampshaded as an unseasonably warm February 14th, hence the lack of coats.
Spoofed in an episode of Hey Arnold!. The first half of the show (each entire episode holds 2 different stories) is about a very bad heat wave over the city that renders almost everyone crazy from the high temperature. At the end of that story, a single snowflake can be seen floating down from above. Part 2 of the episode, a different story, is about how the town is suddenly blanketed with a thick sheet of snow.
On Rugrats, in an early episode a California flag is seen outside the local post office, making you assume that's where the show is set. In the Christmas episode the families rent a cabin in the mountains, so they can have "a real White Christmas". But then, a later episode involves a blizzard happening at the characters' home.
In a related incident, in one episode we get a changing seasons montage, including snow, only to find out it's only been a week. As one character comments: "Crazy Weather we've been having, eh?"
There was an early episode where the babies pretend to be explores in an icy land, all taking place in their snow covered backyard.
From the obscure animated Cabbage Patch Kids Christmas Special: the Kids take one step outside their magical Cabbage Patch (where It's Always Summer) and find themselves in waist-deep snow in a picturesque White Pine forest that might as well be North Conway, New Hampshire. Then they take a ride to "The City" and find an equally picturesque setting with people in furry coats and old brick buildings frosted with ice and snow and such. According to a small sign in a park, the city in question is... Atlanta, Georgia.
Did this episode happen after the one where they acquired the experiment that froze things? In which case, they could have asked the experiment to give them a snowy Christmas. Not to mention that one of the characters is a Mad Scientist who is good friends with the little girl in the title. It's not hard to imagine them deliberately making it snow in any case.
Furthermore, Hawaii does get snow, only it's at the top of Mauna Kea.
Nearly averted in the Christmas episode of Recess, where it is remarked that it is quite warm for December. Then at the end of the episode, down comes the snow.
In the TaleSpinChristmas Episode "Jolly Molly Christmas", Molly dreaming of a white Christmas is a plot point. The climate in Cape Suzette is subtropical or tropical, so the adults keep telling her that this is impossible. In the end, it begins to snow nevertheless.
The Rankin/Bass Christmas special White Christmas has this as part of its storyline.
When winter arrives in Proteus, the snow starts falling and the snowflakes play music for you.
The protagonists of World in Conflict meet Christmas in Cascade Falls, a small town near Fort Teller. The town is evacuated because of the Soviet assault, but the Christmas decorations are still in place—and it's covered in snow. That map is one of the snowiest in the entire game, in fact, possibly even more so than the ones set in Russia.
Films and stories about the life of Jesus usually feature warm if not desert-like weather. However, Christmas nativity scenes sometimes (thought not frequently) portray Jesus' birth as having taken place during snow. Snow in Bethlehem is only slightly more likely than it is in Jerusalem, where it is exceedingly rare (just over 30 days of snow, cumulatively, in the last 60 years), and has never been recorded to occur before January. Not to mention the fact that the Roman Empire saw global temperatures several degrees higher than they are today. However, it's quite likely to have been raining. And this is, of course, assuming that Jesus was actually born in December... many historians are convinced that the Roman Catholic Church placed Christmas in the early winter to coincide with the Winter Solstice in order to attract pagans and that he was more likely born in March or April.
This isn't really debated among historians at all. It's an established fact that the birthday of Christ was moved by the Roman church to coincide with Saturnalia (Roman Winter Solistice), just like nearly every Christian holiday was moved to co-opt a more popular Pagan holiday the locals refused to give up.
The question of time of birth comes from cues in the Biblical text that are not consistent with winter. For one, shepherds would not be tending sheep flocks at night during the winter (but they would in Spring).
At least one Nativity carol, "In the Deep Midwinter", is guilty of this.
Not everyone celebrates Christmas in December. Orthodox Christians celebrate it in January, if only because the Orthodox Church still uses the old Julian calendar, which is currently off by two weeks (Christmas thus being January 7). In the Julian calendar Christmas is still December 25. Note, though, that not all Orthodox Churches use it; some have switched to the modern (Gregorian) calendar and thus celebrate Christmas in line with the non-Orthodox churches.
Beyond the 60th North latitude (or 50th in a deep continental area, like the entirety of Russia), a white Christmas is almost guaranteed. The first snowfall will be in late November, and the permanent snow cover has usually arrived at latest for St. Anna (9th December). The further north, the earlier.
A variation was intentionally averted for many years by the National Football League with the Super Bowl. The game has traditionally been played in late January or early February, when many big football cities are covered in snow. However, up until the NFL pardoned the Meadowlands (just across the Hudson from New York City), who eventually won their bid for the 2014 game, they required host city candidates to have either a domed stadium or average temperatures above 50 degrees Fahrenheit. Now there's a chance that Dreaming of a White Super Bowl will become a reality.
In 2006, freak weather conditions resulted in up to 30cm (a foot) of snow falling in some areas of the Victorian and New South Wales highlands on Christmas Day.
At least one hotel in southern Australia has been known to arrange "Yuletide Festivals" in June, when there is snow in those parts.
In 2009, a December 22-28 snowstorm that hit the Midwestern US hard stretched far enough south to give Dallas, Texas its first White Christmas since 1929. Other parts of Texas had snowfalls of 9 or more inches.
In 2004, a Christmas snowstorm brought significant snowfall to parts of southern Texas and Lousiana. El Campo, Texas, saw 11 inches on Christmas Eve. In Brownsville (a far-South Texas city bordering Mexico), it was their first measurable snowfall since 1899.
The city of Raleigh, capital of North Carolina, has never had snowfall on Christmas Eve or Christmas Day since the city was founded in 1796. Yet there have been white Christmases in other relatively nearby cities (like Durham and Chapel Hill), just NEVER Raleigh itself.
Coastal North Carolina is worse— we're lucky enough for it to snow even once a winter, let alone accumulate. Even then, the snow comes in late January or in February, which are normally colder months than December. Though it did snow on the night of Christmas Day in 2010, and wound up dumping 15 inches of snow the next day. What's worse, the coast is absolutely frigid during the winter, with lows frequently dipping down into the 20s and even teens. It just doesn't snow, ever.
Speaking of Norfolk, Virginia, it does snow there during winter at least once almost every year. But hardly ever in December. Nevertheless, because of cultural conventions, we always (vainly) dreamed of a white Christmas while growing up.