Santa Claus is coming to town: US radar tracks his progress

Father Christmas has taken off from the north pole and is on his busy way to see you, according to a US and Canadian defence organisation that is tracking his sleigh's progress across the globe.

The North American Aerospace Defence Command (Norad) is following his once-yearly 24-hour delivery using radar, satellites, "Santa cams" and fighter jets. Timing his arrivals for when children are asleep, the red-suited present-giver generally heads first for the South Pacific before starting his first calls, moving on to New Zealand, Australia and moving westwards round the globe.

The monitoring service by Colorado-based Norad – main job defending the US and Canada from nuclear missile attack – depends partly on the infrared signal from the glowing nose of Rudolph, the most famous of Santa's reindeer. It has become an internet favourite with children following through social networking sites such as Facebook and Twitter.

"Keep in mind, Santa's route can be affected by weather, so it's really unpredictable," a Norad spokesman said. "Norad co-ordinates with Santa's elf launch staff to confirm his launch time, but from that point on, Santa calls the shots. We just track him.

"Norad tracks Santa, but only Santa knows his route, which means we cannot predict where and when he will arrive at your house," he said. "We do, however, know from history that it appears he arrives only when children are asleep. In most countries, it seems Santa arrives between 9pm and midnight on 24 December. If children are still awake when Santa arrives, he moves on to other houses. He returns later … but only when the children are asleep."

Norad intelligence reports indicate Father Christmas does not experience time the way we do. "His trip seems to take 24 hours to us, but to Santa it might last days, weeks or even months. Santa would not want to rush the important job of delivering presents to children and spreading joy to everyone, so the only logical conclusion is that Santa somehow functions within his own time-space continuum.

"Based on flight profile data gathered from over 50 years of radar and satellite tracking, Norad concludes that Santa probably stands about 5ft 7in (1.7 metres) tall and weighs approximately 260lb (118kg). Based on fighter-aircraft photos, we know he has a generous girth, rosy cheeks from sleigh-riding in cold weather, and a flowing white beard." Norad cannot explain, however, how he gets down chimneys.

The tradition of tracking Santa's sleigh started in 1955 when a misprinted phone number in an advertisement for the retailer Sears Roebuck meant calls for Father Christmas were directed to the hotline for the commander in chief of Norad's predecessor. After receiving calls from excited children wanting to speak with Father Christmas, the commander decided to start the service.

The system knows when Father Christmas has taken off through its 47-installation radar system, then uses its satellites 22,300 miles above the Earth's surface to locate the heat from Rudolph's nose.

In 1998, when the tracking system became available on the internet, Norad added a global system of digital cameras taking pictures and videos of his journey. As Father Christmas approaches north America, Canadian and US jets intercept and welcome the hurtling sleigh.

At just after noon the Norad Twitter feed @noradsanta put out a tweet saying, "#Santa just flew through Honiara, capital of the Solomon Islands. We could use some time on the beach … it's chilly @noradnorthcom!". A few minutes later it added, "He is going to Gizo, Solomon Islands!"

Father Christmas was not available for comment, but a spokes-elf at his north pole headquarters said: "Santa left on time today and is looking forward to his annual round of present-giving. He has presents ready for delivery for every child who has been good this year. Merry Christmas!"