Magazine “Insight” No.6 (PDF) - Carl F. Bucherer

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Stylishlytakingthe weeks
in itsstride.
“Time iswhat aclock measures,” Albert
Einstein once said. In order tomeasure
time, wehave todivide itinto individual
intervals. Today, we think ofitinterms of
seconds, minutes, hours, days or months.
However, it all becomes more problematic
when we introducethe numbersofthe
calendar weeks. Ayear, of course, comprises
twelve months, but the number ofweeks
varies. Some years we have 52 weeks, others
53. The attempt tocreate asystematic
calendar for the weeks inthe year dates back
historically tothe development of the Gregorian
calendar, which divided the year
into 52 complete weeks, or 364 days. The
remaining two or three days are then integrated
either in an additional 53rd week
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or into the first week of the new year. As a
result,every five or sixyears we have an extra
week in the calendar. In a400-year cycle,
we thus have 71 years with “leap weeks”, as
they are known, and 97 leap years –those
with 29 days in February.
Different countries,
Different waysofcounting.
In the course ofhistory, different parts of
the world have evolved different ways of
counting the weeks in the year. In the US,
for instance, the first calendar week ofthe
year always starts onJanuary 1, regardless
of what day ithappens to be. Itcan therefore
be anything from one toseven days in
length. Asaresult, there can bebetween
52 and 54calendar weeks per year, of which
at least one is an incomplete week. On
top ofthis, the first day ofthe week in the
US is always Sunday.