Sure, it's warm and sunny in Southern California this Christmas, but that won't stop people from ice skating!
After all, there are outdoor rinks in downtown Los Angeles, Santa Monica and Long Beach, where, despite the weather, the ice is always cold. (You can see a list of locations here)
So how does that water stay at freezing in 70 degree weather?
It has to do with a substance called propylene glycol, says Willy Bietak, president of Bietak Productions. His company installed outdoor rinks at Pershing Square and by the Queen Mary in Long Beach.
Beitak says propylene glycol can get much colder than the freezing temperature of water and still stay a liquid.
"It's similar to what cars use to keep the radiator from freezing up," Bietak noted.
The propylene glycol is chilled to anywhere from 5 to 15 degrees below freezing using a large refrigeration system. Then it's run through pipes housed in aluminum panels that sit directly under the ice itself, Bietak says.
The glycol cools these panels to very cold temperatures and the panels in turn cool the ice above them.
"And that's how you keep the ice cold," Bietak said.
He points out that different kinds of ice skating require different temperatures of ice.
For instance, you might run glycol at 15 degrees Fahrenheit for an ice hockey rink where a very frozen surface is crucial for enabling a puck to glide effortlessly.
But he says for figure skating, you'd probably want to keep the glycol closer to 25 degrees Fahrenheit.
Bietak says this warmer temperatures creates a "soft, smooth, soapy surface where you have a good edge."
He should know, before getting into the ice rink business Bietak skated competitively in his native country of Austria. He even participated in the 1964 and 1968 Winter Olympics.
Still, you don't have to be a professional to enjoy the feeling of slicing the ice on a warm, sunny Southern California afternoon.
Open ice rinks in SoCal