FreeBSD handles leapsecond correctly

Rich Wales richw at
Tue Jan 3 18:02:44 PST 2006

Peter Jeremy wrote:

> The Islamic calendar (at least the concensus from some googling)
> appears to have 11 leap years in a 30 (lunar) year cycle . . .

AFAIK, no, this is not correct.  The Islamic calendar is a 12-month,
strictly lunar (=not= lunisolar) calendar.  The Islamic year is 11
days shorter than a solar year, and there is =no= correction for
this discrepancy, so any given Islamic month/day will drift through
the seasons over a period of about 33 years.

This is why, for example, the Islamic month of fasting (Ramadan) is
a little earlier every year (same lunar month, but different solar
calendar dates).

> . . . and it seems that there isn't even general agreement on
> which years are leap years.

As I said, there's no such thing as a "leap year" in the Islamic
calendar.  Were you perhaps reading about how the start of each
month (and, thus, the length of each month) is traditionally
determined by actual observation of the young crescent moon?

Rich Wales
richw at

More information about the freebsd-current mailing list