REPRESENTATION
OF
DATE
AND
TIME
DATA
STANDARD
Standard
No.:
1­
19934
Version
2
 
Final
DRAFT
July
26,
2005
This
standard
has
been
produced
through
the
Environmental
Data
Standards
Council
(
EDSC).

The
Environmental
Data
Standards
Council
(
EDSC)
is
a
partnership
among
US
EPA,
States
and
Tribal
partners
to
promote
the
efficient
sharing
of
environmental
information
through
the
development
and
adoption
of
data
standards.
More
information
about
the
EDSC
is
available
at
www.
envdatastandards.
net.
Representation
of
Date
and
Time
Data
Standard
Std
No.:
1­
19934
Version
2.0
 
Final
Draft
July
26,
2005
Page
2
Foreword
The
Environmental
Data
Standards
Council
(
EDSC)
identifies,
prioritizes
and
pursues
the
creation
of
data
standards
for
those
areas
where
information
exchange
standards
will
provide
the
most
value
in
achieving
environmental
results.
The
Council
involves
Tribes
and
Tribal
Nations,
state
and
federal
agencies
in
the
development
of
the
standards
and
then
provides
the
draft
materials
for
general
review.
Business
groups,
non­
governmental
organizations,
and
other
interested
parties
may
then
provide
input
and
comment
for
Council
consideration
and
standard
finalization.
Draft
and
final
standards
are
available
at
http://
www.
envdatastandards.
net.

1.0
INTRODUCTION
This
is
a
format
standard
which
indicates
how
one
displays
a
particular
day
within
a
Gregorian
calendar
month
and
specifies
an
instance
of
time
in
the
day.
Time
is
expressed
in
Coordinated
Universal
Time
(
UTC).
UTC
is
the
official
time
scale,
maintained
by
the
Bureau
International
des
Poids
et
Mesures
(
BIPM),
and
the
International
Earth
Rotation
Service
(
IERS).
Examples
of
the
formats
follow:

a.
Date
only
format
When
the
need
is
for
an
expression
only
of
a
calendar
date,
then
the
complete
representation
shall
be
a
single
numeric
data
element
comprising
eight
digits,
where
[
YYYY]
represents
a
calendar
year,
[
MM]
the
ordinal
number
of
a
calendar
month
within
the
calendar
year,
and
[
DD]
the
ordinal
number
of
a
day
within
the
calendar
month.

Extended
format:
YYYY­
MM­
DD
EXAMPLE
1985­
04­
12
b.
Time
with
difference
between
local
time
and
Coordinated
Universal
Time.
The
complete
representation
of
the
time
of
27
minutes
46
seconds
past
15
hours
locally
in
Geneva
(
normally
one
hour
ahead
of
UTC),
and
in
New
York
(
five
hours
behind
UTC),
together
with
the
indication
of
the
difference
between
the
local
time
and
UTC,
are
used
as
examples.

Extended
format:
hh:
mm:
ss
±
hh:
mm
EXAMPLE
15:
27:
46+
01:
00
or
15:
27:
46
 
05:
00
If
a
lesser
degree
of
precision
is
needed,
either
two
or
four
digits
may
be
omitted
from
the
representation.

Extended
format:
hh:
mm
±
hh:
mm
EXAMPLE
15:
27+
01:
00
or
15:
27
 
05:
00
Extended
format:
hh
±
hh:
mm
EXAMPLE
15+
01:
00
or
15
 
05:
00
c.
Date
and
time
example.
The
complete
representation
of
the
date/
time
of
April
12,
1998
at
27
minutes
46
seconds
past
15
hours
locally
in
Geneva
(
normally
one
hour
ahead
of
UTC),
and
in
New
York
(
five
hours
behind
UTC),
together
with
the
indication
of
the
difference
between
the
local
time
and
UTC,
are
used
as
examples.

Extended
format:
YYYY­
MM­
DDThh:
mm:
ss
±
hh:
mm
EXAMPLE
1998­
04­
12T15:
27:
46+
01:
00
1998­
04­
12T15:
27:
46
 
05:
00
1.1
Scope
This
standard
provides
and
describes
data
groupings
that
are
used
for
exchange
of
Date
and
Time
data
and
information.

1.2
References
to
Other
Data
Standards
This
data
standard
relies
on
other
data
standards
to
make
it
complete
and
to
provide
the
necessary
support.
As
such,
users
should
reference
the
normative
standards,
listed
below,
and
consider
them
integral
to
the
Representation
of
Date
and
Time
Standard:
Representation
of
Date
and
Time
Data
Standard
Std
No.:
1­
19934
Version
2.0
 
Final
Draft
July
26,
2005
Page
3
 
ISO
8601:
2000
Data
elements
and
interchange
formats
­­
Information
interchange
­­
Representation
of
dates
and
times
 
ANSI
INCITS
30­
1997
Data
elements
and
interchange
formats
­­
Information
interchange
­­
Representation
of
dates
and
times
 
ANSI
INCITS
310­
1998
Data
elements
and
interchange
formats
­­
Information
interchange
­­
Representation
of
dates
and
times
 
W3C
Recommendation
XML
Schema
Part
2:
Datatypes
02
May
2001
1.3
Terms
and
Definitions
For
the
purposes
of
this
document,
the
following
terms
and
definitions
apply:

Term
Definition
Coordinated
Universal
Time
(
UTC)
The
official
coordinate
time
scale
for
the
Earth
defined
on
the
"
rotating
geoid."
[
Rec.
ITU­
R
TF.
1010,
Relativistic
Effects
in
a
Coordinate
Time
System
in
the
Vicinity
of
the
Earth].
The
time
scale,
maintained
by
the
Bureau
International
des
Poids
et
Mesures
(
BIPM),
and
the
International
Earth
Rotation
Service
(
IERS),
which
forms
the
basis
of
a
coordinated
dissemination
of
standard
frequencies
and
time
signals
[
Rec
686,
Glossary].
Date
A
particular
day
within
a
Gregorian
calendar
month.

Time
In
English,
`
time'
is
used
to
specify
an
instant
(
time
of
day).
"[
ITU­
R
Recommendations,
1994
TF
Series
Volume,
Time
Signals
and
Frequency
Standards
Emissions
(
Recommendation
686,
Glossary)]."
A
particular
point
in
the
stream
of
time
of
at
a
particular
place
(
which
may
or
may
not
be
specified
in
terms
of
a
particular
date):
a
specific
hour,
or
minute,
or
second,
or
fraction
of
a
second
in
a
day
at
a
specific
place.

Leap
Second
A
leap
second
is
a
second
of
time
intentionally
inserted
in
or
deleted
from
the
UTC
time
stream
to
keep
it
approximately
compatible
with
the
rotation
of
the
Earth.
An
inserted
second
is
called
a
positive
leap
second
and
an
omitted
second
is
called
a
negative
leap
second.
For
the
purposes
of
this
standard,
a
positive
leap
second
is
labeled
"
60"
and
a
negative
leap
second
is
labeled
"
58"
(
there
being
no
second
with
the
label
"
59"
in
a
minute
with
a
negative
leap
second).

1.4
Implementation
Users
are
encouraged
to
use
the
XML
registry
housed
on
the
Exchange
Network
Web
site
(
http://
www.
exchangenetwork.
net)
to
download
schema
components
for
the
construction
of
XML
schema
flows.

1.5
Document
Structure
The
structure
of
this
document
is
briefly
described
below:

a.
Section
2.0
Representation
of
Date
and
Time
Data
Standard
Diagram,
illustrates
the
principal
data
groupings
contained
within
this
standard.

b.
Section
3.0
Representation
of
Date
and
Time
Data
Standard
Table,
provides
information
on
the
high
level,
intermediate
and
elemental
representation
of
date
and
time
data
groupings.
Where
applicable,
for
each
level
of
this
data
standard
a
definition,
XML
tag,
note(
s),
example
list
of
values
and
format
are
provided.
The
format
column
may
include
the
number
of
characters
for
the
associated
data
element,
where
"
A"
specifies
alphanumeric
and
"
N"
designates
numeric.

c.
Data
Standard
Numbering:
For
purposes
of
clarity
and
to
enhance
understanding
of
data
standard
hierarchy
and
relationships,
each
data
group
is
numerically
classified
from
the
primary
to
the
elemental
level.
Representation
of
Date
and
Time
Data
Standard
Std
No.:
1­
19934
Version
2.0
 
Final
Draft
July
26,
2005
Page
4
d.
Code
and
Identifier
metadata:
Based
on
the
business
need,
additional
metadata
may
be
required
to
sufficiently
describe
an
identifier
or
a
code.
A
note
regarding
this
additional
metadata
is
included
in
the
notes
column
for
identifier
and
code
elements.
Additional
metadata
for
identifiers
may
include:

 
Code
List
Identifier,
which
is
a
standardized
reference
to
the
context
or
source
of
the
set
of
codes
Additional
metadata
for
codes
may
include:

 
Code
List
Identifier,
which
is
a
standardized
reference
to
the
context
or
source
of
the
set
of
codes.

 
Code
List
Version
Identifier,
which
identifies
the
particular
version
of
the
set
of
codes.

 
Code
List
Version
Agency
Identifier,
which
identifies
the
agency
responsible
for
maintaining
the
set
of
codes.

 
Code
List
Name,
which
describes
the
corresponding
name
for
which
the
code
represents.
e.
Appendix
A,
Representation
of
Date
and
Time
Data
Standard
Structure
Diagram,
illustrates
the
hierarchical
classification
of
the
representation
of
date
and
time
data
standard.
This
diagram
enables
business
and
technical
users
of
this
standard
to
quickly
understand
its
general
content
and
complexity.
Representation
of
Date
and
Time
Data
Standard
Std
No.:
1­
19934
Version
2.0
 
Final
Draft
July
26,
2005
Page
5
2.0
REPRESENTATION
OF
DATE
AND
TIME
DATA
STANDARD
DIAGRAM
This
diagram
specifies
the
major
data
groups
that
may
be
used
to
identify
the
characteristics
and/
or
to
catalog
a
date
and
time.

Representation
of
Date
and
Time
Data
Standard
1.0
Date
2.0
Time
Representation
of
Date
and
Time
Data
Standard
Std
No.:
1­
19934
Version
2.0
 
Final
Draft
July
26,
2005
Page
6
3.0
REPRESENTATION
OF
DATE
AND
TIME
DATA
STANDARD
TABLE
1.0
Date
Definition:
A
particular
year,
month,
and
day
of
the
Gregorian
calendar.

Relationship:
Calendar
date
data
is
represented
as
an
eight­
digit
sequence,
composed
of
numeric
characters
in
the
format
YYYY­
MM­
DD,
where
YYYY
represents
the
calendar
year,

MM
represents
the
calendar
month
of
the
year,
and
DD
represents
the
calendar
day
of
the
month,

sequenced
from
high
order
to
low
order
(
i.
e.
year,
month,
day,
from
left
to
right,
as
shown
above).

Separators
are
used
between
the
elements
for
the
interchange
of
date.
This
is
the
"
extended"
representation
in
ISO
8601
to
separate
the
elements
"
year"
and
"
month",
"
month"
and
"
day"
the
separator
is
"­".
To
separate
date
and
time
the
separator
is
"
T".

Note:
None.

XML
Tag:
Date.

Name
Definition
Notes
Format
XML
Tags
1.1
Year
Code
A
code
representing
a
particular
year
according
to
the
Gregorian
calendar.
The
numbers
that
represent
year
shall
include
leading
zeros
whenever
their
respective
values
are
less
than
1000.
N(
4)
YYYY
1.2
Month
Code
A
code
representing
a
particular
month
within
a
Gregorian
calendar
year.
The
beginning
of
a
month
within
a
year
shall
be
represented
by
a
two­
digit
decimal
number
ranging
from
01
through
12.

The
numbers
that
represent
the
month
of
a
year
shall
include
leading
zeros
whenever
their
respective
values
contain
only
one
digit.
N(
2)
MM
1.3
Day
Code
A
code
representing
a
particular
day
within
a
Gregorian
calendar
month.
The
beginning
of
a
day
within
a
month
shall
be
represented
by
a
two­
digit
decimal
number
ranging
from
01
through
31
depending
upon
the
number
of
days
in
the
month.

The
numbers
that
represent
the
day
of
the
month
shall
include
leading
zeros
whenever
their
respective
values
contain
only
one
digit.
N(
2)
DD
Representation
of
Date
and
Time
Data
Standard
Std
No.:
1­
19934
Version
2.0
 
Final
Draft
July
26,
2005
Page
7
2.0
Time
Definition:
A
particular
point
in
the
stream
of
time
at
a
particular
place
(
which
may
or
may
not
be
specified
in
terms
of
a
particular
date):
a
specific
hour,
or
minute,
or
second
in
a
day
at
a
specific
place.

Relationship:
Time
data
is
represented
as
an
eight­
14­
character
sequence,
in
the
format
hh:
mm:
ss
±
hh:
mm.
Where
hh
represents
the
hour;
mm
represents
the
minute;
ss
represents
the
second;
±
hh:
mm
represents
the
difference
with
UTC.
To
separate
date
and
time
the
separator
is
"
T".

Separators
are
used
between
the
elements
for
the
interchange
of
time.
This
is
the
"
extended"
representation
in
ISO
8601.

To
separate
the
elements
"
hour"
and
"
minute",
and
"
minute"
and
"
second"
the
separator
is
":"

Note:
To
indicate
local
time
and
the
difference
between
local
time
and
UTC,
the
representation
of
the
difference
shall
be
appended
to
the
representation
of
the
local
time
following
immediately,
without
space,
the
lowest
order
(
extreme
righthand
component
of
the
local
time
expression,
which,
in
this
case,
shall
always
include
hours,
minutes,
and
seconds.
The
difference
between
local
time
and
UTC
shall
be
expressed
in
hours­
and­
minutes.

XML
Tag:
Time
Name
Definition
Notes
Format
XML
Tags
2.1
Hour
Code
A
code
representing
60
minutes,

each
labeled
consecutively
in
the
24­

hour
timekeeping
system
from
0
through
23
beginning
with
the
start
of
the
first
minute
after
the
beginning
of
the
hour.
Ordinarily,
an
hour
is
one
24
th
of
a
day.
The
beginning
of
an
hour
of
day
shall
be
represented
using
the
24­
hour
timekeeping
system
by
recording
a
twodigit
decimal
number
ranging
from
00
through
23.

The
numbers
that
represent
hour
shall
include
leading
zeros
whenever
their
respective
values
contain
only
one
digit.

An
hour
which
contains
a
leap
second
will
have
one
extra
or
one
less
second,

depending
upon
whether
the
leap
second
is
positive
or
negative,
respectively.
N(
2)
hh
Representation
of
Date
and
Time
Data
Standard
Std
No.:
1­
19934
Version
2.0
 
Final
Draft
July
26,
2005
Page
8
Name
Definition
Notes
Format
XML
Tags
2.2
Minute
Code
A
code
representing
60
seconds,

each
labeled
consecutively
in
the
24­

hour
timekeeping
system
from
0
through
59
beginning
with
the
start
of
the
first
second
after
the
beginning
of
the
minute.
Ordinarily,
a
minute
is
one
60
th
of
an
hour.
The
beginning
of
a
minute
within
an
hour
of
the
day
shall
be
represented
by
a
two­
digit
decimal
number
ranging
from
00
through
59.
The
numbers
that
represent
a
minute
shall
include
leading
zeros
whenever
their
respective
values
contain
only
one
digit.

A
minute
which
contains
a
leap
second
will
have
61
or
59
seconds,
depending
upon
whether
the
leap
second
is
positive
or
negative,
respectively.
N(
2)
mm
2.3
Second
Code
Ordinarily,
a
code
representing
second
is
one
60
th
of
a
minute.

A
code
representing
"
the
duration
of
9
192
631
770
periods
of
the
radiation
corresponding
to
the
transition
between
the
two
hyperfine
levels
of
the
ground
state
of
the
cesium
atom­
133."
(
XIII
e
Conférence
Générale
des
Poids
et
Mesures,

1967.)
The
allowable
two­
digit
decimal
numbers
for
seconds
ordinarily
range
from
00
through
59.

The
numbers
that
represent
a
second
shall
include
leading
zeros
whenever
their
respective
values
contain
only
one
digit.

If
the
magnitude
of
the
number
is
less
than
unity,
the
decimal
sign
shall
be
preceded
by
two
zeros.

The
number
of
digits
in
the
decimal
fraction
shall
be
determined
by
the
interchange
parties,
dependent
upon
the
application.

The
format
shall
be
[
hhmmss.
ss]
as
appropriate
with
as
many
digits
as
necessary
following
the
decimal
sign.
A
decimal
fraction
shall
have
at
least
one
digit.

The
two­
digit
decimal
number
60
is
reserved
for
representing
a
positive
leap
second.
The
allowed
two­
digit
decimal
numbers
range
from
00
to
only
58
in
the
last
minute
of
a
day
having
a
negative
leap
second.
Information
systems
may
be
recording
time
with
leap
seconds
if,
for
example,
they
synchronize
with
atomic
clocks
such
as
those
managed
at
NIST
or
the
Naval
N(
2).(
n)
ss.
ssss
Representation
of
Date
and
Time
Data
Standard
Std
No.:
1­
19934
Version
2.0
 
Final
Draft
July
26,
2005
Page
9
Name
Definition
Notes
Format
XML
Tags
Observatory.

2.4
UTC
Difference
The
signed
difference
between
local
time
and
Coordinated
Universal
Time
(
UTC).
The
difference
between
local
time
and
UTC
shall
be
expressed
in
hours
and
minutes,

with
a
":"
separating
the
hours
and
minutes.

It
shall
be
expressed
as
positive
(
i.
e.
with
the
leading
plus
sign
[+])
if
the
local
time
is
ahead
of
or
equal
to
UTC
and
as
negative
(
i.
e.
with
the
leading
minus
sign
[
 
]
)
if
it
is
behind
UTC.
±
nn:
nn
UTCDifference
Representation
of
Date
and
Time
Data
Standard
Std
No.:
1­
19934
Version
2.0
 
Final
Draft
July
26,
2005
Page
10
APPENDIX
A
Representation
of
Date
and
Time
Data
Standard
Structure
Diagram
Representation
of
Date
and
Time
Data
Standard
1.0
Date
1.1
Year
Code
1.2
Month
Code
1.3
Day
Code
2.0
Time
2.1
Hour
Code
2.2
Minute
Code
2.3
Second
Code
2.4
UTC
Difference
