Birthday facts
Born on December 21.
Everyone born on December 21 is a Sagittarius — ruled by Jupiter, packed, gone, unreachable. The stone is turquoise, the flower narcissus, and the day is shared with Jane Fonda and Emmanuel Macron.
Your book
Born on December 21? Add the year.
Then it is a pop-up book: the sky the day you arrived, the No. 1 that week, the president, what a stamp cost, your life in weeks, and who was exactly your age when they did the thing they are known for — and at the end, a birthday poster of the day, engraved, to take home. One field. The date lives after the # in the link, which no server sees — nothing about you leaves your browser.
Making it for someone else? Send it as a pop-up birthday card.
The old books say
Sagittarius, November 22 to December 21.
The Archer, half horse and aiming somewhere over the horizon; ruled by Jupiter, the planet of more. A fire sign, and the books credit it with optimism, honesty to a fault and a need to be elsewhere — the traveller, the student, the one with the ticket already booked. Its people are supposed to say the true thing before checking whether anyone wanted it said. The tradition forgives them, mostly.
Astrology, reported rather than endorsed — the astronomy is the part of the book that is real.
Good company
Also born on December 21.
The names most looked up among everyone who shares the day — leaning on the ones who last.
On this day
What December 21 has seen.
It is December solstice (15:03 UTC, 2025).
The calendar
When December 21 falls.
A Monday in 2026, a Tuesday in 2027, a Thursday in 2028, a Friday in 2029, and a Saturday in 2030.