Throughout the year NORAD , the North American Aerospace Defense Command, busies itself with monitoring the skies for airplanes, missiles, space launches and other things that fly in the skies.

But on Christmas, NORAD focuses on scanning the skies for Santa as he travels in his sleigh around the world. There’s even a Santa Tracker so we can follow along.

From years of tracking Santa, NORAD has learned a few things:

While it can’t predict when Santa will arrive at a certain house, NORAD does know that “he arrives only when children are asleep.”

NORAD also knows Santa’s preferred flying route:

“Santa usually starts at the International Date Line in the Pacific Ocean and travels west. So, historically, Santa visits the South Pacific first, then New Zealand and Australia. After that, he shoots up to Japan, over to Asia, across to Africa, then onto Western Europe, Canada, the United States, Mexico and Central and South America. Keep in mind, Santa’s route can be affected by weather, so it’s really unpredictable. NORAD coordinates with Santa’s Elf Launch Staff to confirm his launch time, but from that point on, Santa calls the shots. We just track him!”