Two teenage girls, Samantha Elizabeth "Sam" Kwan and Allison Rachel "Allie" Thompson, find a weather machine at a shack in the woods. After learning of its controls, they use it to make it snow in Los Angeles. It is fun for everybody who it affected.
It turns out that the machine belongs to Santa Claus and he informs Mrs. Claus about this. To help him, she sends Crumpet and Sparky, two elves who look nothing like the traditional design (in other words, as one of them mentions, they are "not 3 feet tall and have squeaky voices").
Unfortunately, a boring weatherman named Edwin Hadley tries to figure out what's causing the strange weather and tracks it down to keep himself from getting fired by his boss Mr. Martino. He expects him to not act all boring and get down to the bottom of the sudden snow appearances.
When Sparky and Crumpet catch up to Santa at the shack, they find a clue being a footprint of a type of girl shoes that are only made in California. They set off to interrogate each girl on the naughty list that wears those type of shoes.
Soon the snowstorm gets so large that it spreads to San Francisco and Allie's dad gets snowed in at the airport and may not make it home in time for Christmas. She tries to turn the machine off, but overnight it turns itself back on and creates a blizzard. They are unable to make it do anything now. Sam shares sad stories with Allie about how her dad would spend Christmas, while Allie is sad about hers missing it.
During the blizzard, Mr. Martino tells Edwin to handle the story about the cast of Friends not being able to leave their studio. He manages to trace the weather phenomenon to Allie's house. Due to traffic, he manages to borrow a man's snowmobile.
When Sam and Allie head to the shack to get the flashlights, they encounter Santa, Crumpet, and Sparky who identify Allie as the next person on their naughty list. They managed to get proof that he's Santa when he tells all about them and the machine.
Edwin arrives at Allie's house and manages to gain entry. He manages to find the machine after her brother found it and berats him for messing with it. Upon being cornered in her room by the girls, Santa, and the elves, he announces his plans to be the best weatherman in history and feign more publicity on television attempts. During his escape, he sees the man he borrowed the snowmobile from and crashes into a chocolate factory where he falls into a chocolate vat. The group follow his trail into the factory and follows his chocolatey trail. Sparky follows him up into the raftings where he falls into a box of cotton candy. The group then reclaims the machine.
At Santa's shack, he then works to find the problem in the machine. With Sam and Allie's help, they manage to fix it (Santa forgot to put in the right batteries) and stop the snow. Santa then tells Edwin that there is another type of job that deals with weather.
Crumpet and Sparky pick up Allie's dad just in time for Christmas morning. Meanwhile, Edwin gets a job in the Arctic teaching scientists about the weather.
|Hallee Hirsh||Allison Thompson|
|Spencer Breslin||Joey Thompson|
|Hallie Todd||Michelle Thompson|
|Greg Kean||Steve Thompson|
|Brenda Song||Samantha Kwan|
|Laara Ong||Linda Kwan|
|Bill Fagerbakke||Sparky the elf|
|John Salley||Crumpet the elf|
|Susan Ruttan||Mrs. Claus|
|John Lowe||Santa Claus|
|Jason Schombing||Mr. Martino|
|Peter Scolari||Edwin Hadley|
|Daniel Boileau||Horace (Snowmobile driver)|
|Jo-Ann Fernandes||Mrs. Lopez|
|Karen Holness||National Weatherperson|
|Donna Lysell||News broadcaster|
|Brittany Moldowan||Mary Jo|
|Angela Moore||Mary Jo's mother|
|Colin O'Neill||Blake Lynch|
|Dale Reynolds||News Weatherperson|
|Greg Beeman (uncredited)||News Director|
|Ian Martin (uncredited)||Weatherman Student|