ISO
8601:2000(E)
©
ISO
2000
All
rights
reserved
7
calendar
year
[0001]
differ
from
the
year
numbers
in
the
"BC/AD
calendar
system",
where
the
year
"1
BC"
is
followed
by
the
year
"1
AD".
In
the
Gregorian
calendar
each
year
is
divided
in
12
sequential
calendar
months
as
indicated
in
Table
1.
Table
1
-
Calendar
months
Calendar
month
number
Calendar
month
name
Number
of
days
in
the
month
Ordinal
dates
of
the
days
in
common
years
Ordinal
dates
of
the
days
in
leap
years
01
January
31
01-31
01-31
02
February
28
(leap
year
29)
32-59
32-60
03
March
31
60-90
61-91
04
April
30
91-120
92-121
05
May
31
121-151
122-152
06
June
30
152-181
153-182
07
July
31
182-212
183-213
08
August
31
213-243
214-244
09
September
30
244-273
245-274
10
October
31
274-304
275-305
11
November
30
305-334
306-335
12
December
31
335-365
336-366
4.3.2.2
The
calendar
week
In
parallel
with
the
reference
system
described
in
4.3.2.1,
there
is
a
reference
system
based
on
an
unbounded
series
of
contiguous
calendar
weeks.
Each
calendar
week
has
seven
calendar
days
as
indicated
in
Table
2.
Table
2
-
Calendar
days
Ordinal
day
number
in
the
week
Calendar
day
name
01
Monday
02
Tuesday
03
Wednesday
04
Thursday
05
Friday
06
Saturday
07
Sunday
The
reference
point
of
the
week
calendar
assigns
Saturday
to
2000
January
1.
A
calendar
week
is
identified
within
a
calendar
year
by
the
calendar
week
number.
This
is
its
ordinal
position
within
the
year,
applying
the
rule
that
the
first
calendar
week
of
a
year
is
the
one
that
includes
the
first
Thursday
of
that
year
