Sleeps, not just days
Children count to Christmas in sleeps, so the countdown shows those as well: the number of nights left before Christmas morning. Sleeps follow the calendar rather than the clock, so at 11 pm on the 23rd it is still two sleeps, even though Christmas is barely a day away.
The row of bulbs along the top changes pace as Christmas gets closer: a slow, uneven twinkle for most of the month, a brisker sparkle in the last 24 hours, a chase in the final minute and every bulb on at once when the clock strikes twelve.
The row of bulbs along the top changes pace as Christmas gets closer: a slow, uneven twinkle for most of the month, a brisker sparkle in the last 24 hours, a chase in the final minute and every bulb on at once when the clock strikes twelve. You can tell roughly how near it is from across the room without reading the digits.
On Christmas Day
The page does not roll over to next year at midnight. It shows Merry Christmas for the whole of 25 December, then begins counting to next Christmas on the 26th.