What sign is my birthday?

How your birthday gives your sign

Your zodiac sign, the one people ask about, is the sign the Sun was in when you were born. The Sun takes a year to go round the twelve signs, a little under a degree a day, so each calendar date lands on almost the same degree every year.

Almost, because the calendar year and the solar year do not line up exactly. The leap-year cycle makes the moment the Sun changes sign drift by up to a day. That is why a handful of dates each month are cusp days: the sign depends on the birth year, the hour and the time zone. Each of those pages lists the years.

Every sign is also split into three decans of ten degrees. We use the triplicity system, where the three decans of a sign belong to the three signs of its element. It is one reason two people with the same Sun sign but birthdays three weeks apart can feel different.