Riyadh Timezone

[Roedy Green]

Java TimeZone classes say:

Offset DST
3.117777777777778 3.117777777777778 Asia/Riyadh87
GMT+03:07
3.117777777777778 3.117777777777778 Asia/Riyadh88
GMT+03:07
3.117777777777778 3.117777777777778 Asia/Riyadh89
GMT+03:07
3.117777777777778 3.117777777777778 Mideast/Riyadh87
GMT+03:07
3.117777777777778 3.117777777777778 Mideast/Riyadh88
GMT+03:07
3.117777777777778 3.117777777777778 Mideast/Riyadh89
GMT+03:07

In other words 3 hours and 7 minutes, most peculiar. What is even
more peculiar is every website I checked on the web says the offset is
a simple three hours. What gives? Where did those 7 minutes come
from?

I speculate it is used at Mecca to arrange for true solar time.

 

[Roedy Green]

In other words 3 hours and 7 minutes, most peculiar. What is even
more peculiar is every website I checked on the web says the offset is
a simple three hours. What gives? Where did those 7 minutes come
from?

there is also an entry for a plain 3.0 hours.

3.0 3.0 Asia/Riyadh Arabia Standard Time

 

[Roedy Green]

Java TimeZone classes say:

Offset DST
3.117777777777778 3.117777777777778 Asia/Riyadh87
GMT+03:07
3.117777777777778 3.117777777777778 Asia/Riyadh88
GMT+03:07
3.117777777777778 3.117777777777778 Asia/Riyadh89
GMT+03:07
3.117777777777778 3.117777777777778 Mideast/Riyadh87
GMT+03:07
3.117777777777778 3.117777777777778 Mideast/Riyadh88
GMT+03:07
3.117777777777778 3.117777777777778 Mideast/Riyadh89
GMT+03:07

In other words 3 hours and 7 minutes, most peculiar. What is even
more peculiar is every website I checked on the web says the offset is
a simple three hours. What gives? Where did those 7 minutes come
from?

I speculate it is used at Mecca to arrange for true solar time.

this is my best guess as to what is going on:

Use Asia/Riyadh for Arabia Standard Time. Asia/Riyadh87, Asia/Riyadh88
and Asia/Riyadh89 are 3 hours and 7 minutes east of UTC so presumably
that Muslims could use natural sun time at Mecca in 1987 through 1989.

 

[Gordon Beaton]

Java TimeZone classes say:

Offset DST
3.117777777777778 3.117777777777778 Asia/Riyadh87
GMT+03:07
3.117777777777778 3.117777777777778 Asia/Riyadh88
GMT+03:07
3.117777777777778 3.117777777777778 Asia/Riyadh89
GMT+03:07
3.117777777777778 3.117777777777778 Mideast/Riyadh87
GMT+03:07
3.117777777777778 3.117777777777778 Mideast/Riyadh88
GMT+03:07
3.117777777777778 3.117777777777778 Mideast/Riyadh89
GMT+03:07

In other words 3 hours and 7 minutes, most peculiar. What is even
more peculiar is every website I checked on the web says the offset is
a simple three hours. What gives? Where did those 7 minutes come
from?

I speculate it is used at Mecca to arrange for true solar time.

AFAIK Saudia Arabia used apparent solar time from 1987 to 1989.

/gordon


--

 

[Hunter Gratzner]

Java TimeZone classes say:

Offset DST
3.117777777777778 3.117777777777778 Asia/Riyadh87
GMT+03:07
3.117777777777778 3.117777777777778 Asia/Riyadh88
GMT+03:07
3.117777777777778 3.117777777777778 Asia/Riyadh89
GMT+03:07
3.117777777777778 3.117777777777778 Mideast/Riyadh87
GMT+03:07
3.117777777777778 3.117777777777778 Mideast/Riyadh88
GMT+03:07
3.117777777777778 3.117777777777778 Mideast/Riyadh89
GMT+03:07

In other words 3 hours and 7 minutes, most peculiar. What is even
more peculiar is every website I checked on the web says the offset is
a simple three hours. What gives? Where did those 7 minutes come
from?

The above offset is wrong and right. First it should be 3:07:04 (four
seconds more than you have). Second, these 3:07:04 are kind of an
average. Each individual day in the year is slightly shifted, so that
sunset happens at 00:00 local time. And sunset is the begin of the
Islamic day. They moved what Christians would call midnight to the
sunset, including per-day corrections to make it fit - for that
particular location. At least almost.

Third, in parallel to these three years Riyhad is just using an offset
of 3:00 since 1950 for its normal timezone. Until 1950 it was 3:06:52.

[All offset data courtesy of the National Institute of Health "Olson"
database - from which also Sun took the timezone data for Java. Just
that Sun decided to use an own binary encoding instead of using the
standard one.]

 

[Dr J R Stockton]

In comp.lang.java.programmer message <1192123676.198138.207720@g4g2000hs
f.googlegroups.com>, Thu, 11 Oct 2007 17:27:56, Hunter Gratzner

Third, in parallel to these three years Riyhad is just using an offset
of 3:00 since 1950 for its normal timezone. Until 1950 it was 3:06:52.

Is it known whether anywhere in the world still ever uses, for its civil
time, an offset from GMT/UTC which is not a multiple of fifteen minutes?

Is it known whether there is more than one location which routinely
changes its clocks between winter and summer by an amount other than one
hour?

In each case, can it be confirmed by means independent of the
traditional databases?

 

[Gordon Beaton]

Is it known whether anywhere in the world still ever uses, for its
civil time, an offset from GMT/UTC which is not a multiple of
fifteen minutes?

AFAIK, all are multiples of 30 minutes except Nepal (UTC+5:45) and
Chatham Islands (NZ) (UTC+12:45). The latter is odd in that it's an
offset greater than 12 hours from UTC (and +13:45 in the summer).

Is it known whether there is more than one location which routinely
changes its clocks between winter and summer by an amount other than
one hour?

Lord Howe Island (Aus) changes from UTC+10:30 to UTC+11 in the summer.

I have a vague recollection of someplace that observes 2H DST, but
can't think of one off hand.

/gordon

--

 

[Roedy Green]

(c) John Stockton, Surrey, UK.

I would like to publicly thank Dr. Stockton. It has taken me several
days to incorporate all the corrections and improvements to the Java
glossary he found on time and calendars.

I hope you will find the new versions have more precise language.
in particular see:
http://mindprod.com/jgloss/calendar.html
http://mindprod.com/jgloss/utc.html
http://mindprod.com/jgloss/gmt.html
http://mindprod.com/jgloss/leapyear.html
http://mindprod.com/jgloss/leapsecond.html
http://mindprod.com/jgloss/time.html
http://mindprod.com/jgloss/gregoriancalendar.html
http://mindprod.com/jgloss/timezone.html
http://mindprod.com/jgloss/summertime.html
http://mindprod.com/jgloss/missingdays.html
http://mindprod.com/applet/holidays.html

 

[Hunter Gratzner]

Is it known whether anywhere in the world still ever uses, for its civil
time, an offset from GMT/UTC which is not a multiple of fifteen minutes?

I would search "the traditional database" for potential candidates.

Is it known whether there is more than one location which routinely
changes its clocks between winter and summer by an amount other than one
hour?

Again I would search "the traditional database" for potential
candidates.

In each case, can it be confirmed by means independent of the
traditional databases?

You didn't say "easily confirmed", so I'd say you can. Once you have
potential candidates, contact the embassy of that country, their local
science academy, their astronomy academy, the leading university, or
whatever you can come up with. Try to find out who has the power to
make the time decision for that region. Locate a copy of the decision,
law, etc. Get it translated into your language. And you have your
confirmation.

Further, "the traditional database" often lists the source of their
information. You could try to obtain that source to verify that it
states what is claimed it states.