What Leap Day is

29 February, added in years divisible by four — except century years not divisible by 400. That correction is what keeps the calendar aligned with the solar year of about 365.2422 days.

Without it the seasons would drift by roughly a day every four years.

Why this date only exists in some years

The countdown at the top of this page is live, and the date beneath it is the next occurrence. This date exists only in leap years — those divisible by four, excluding century years not divisible by 400.

The date follows the Gregorian leap-year rule directly, so it is arithmetic rather than a matter of announcement.

What is coming up next

Once this date passes, the countdown moves on according to the recurrence rule described above. Calculated lunar dates remain estimates until the relevant calendar or local authority confirms them. See the full list of upcoming events, or use the countdown timer for a duration of your own.