Time Zone help

Craven, Isn't there some automatic time zone program that will take care of all this? I know that Oregon Scientific produces many consumer products that self-adjusts to the atomic clock in Colorado. c.i.

BTW, even our t.v. set has a self-adjusting clock. c.i.

Craven, Try this link. http://www.worldtime.org/cgi-bin/wt.cgi

c.i.

c.i.

The date for time zone changes to DST often varies. Tracking the current time is no problem but I'd have to create and maintain a DST server or sync to one.

But I have another solution I'll try soon.

Here is a fairly full list of timezones (due to Java2 SDK1.4.1).
These are Standard Time and DST must be considered independently.

GMT+0.0 :
Africa/Abidjan
Africa/Accra
Africa/Bamako
Africa/Banjul
Africa/Bissau
Africa/Casablanca
Africa/Conakry
Africa/Dakar
Africa/El_Aaiun
Africa/Freetown
Africa/Lome
Africa/Monrovia
Africa/Nouakchott
Africa/Ouagadougou
Africa/Sao_Tome
Africa/Timbuktu
America/Danmarkshavn
Atlantic/Canary
Atlantic/Faeroe
Atlantic/Madeira
Atlantic/Reykjavik
Atlantic/St_Helena
Eire
Etc/GMT
Etc/GMT+0
Etc/GMT-0
Etc/GMT0
Etc/Greenwich
Etc/UCT
Etc/UTC
Etc/Universal
Etc/Zulu
Europe/Belfast
Europe/Dublin
Europe/Lisbon
Europe/London
GB
GB-Eire
GMT
GMT0
Greenwich
Iceland
Portugal
UCT
UTC
Universal
WET
Zulu



GMT-1:00 :
America/Scoresbysund
Atlantic/Azores
Atlantic/Cape_Verde


GMT-2:00 :
America/Noronha
Atlantic/South_Georgia
Brazil/DeNoronha



GMT-3:00 :
AGT
America/Araguaina
America/Belem
America/Buenos_Aires
America/Catamarca
America/Cayenne
America/Cordoba
America/Fortaleza
America/Godthab
America/Jujuy
America/Maceio
America/Mendoza
America/Miquelon
America/Montevideo
America/Paramaribo
America/Recife
America/Rosario
America/Sao_Paulo
BET
Brazil/East


GMT-3:30 :
America/St_Johns
CNT
Canada/Newfoundland

GMT-4:00 :
America/Anguilla
America/Antigua
America/Aruba
America/Asuncion
America/Barbados
America/Boa_Vista
America/Caracas
America/Cuiaba
America/Curacao
America/Dominica
America/Glace_Bay
America/Goose_Bay
America/Grenada
America/Guadeloupe
America/Guyana
America/Halifax
America/La_Paz
America/Manaus
America/Martinique
America/Montserrat
America/Port_of_Spain
America/Porto_Velho
America/Puerto_Rico
America/Santiago
America/Santo_Domingo
America/St_Kitts
America/St_Lucia
America/St_Thomas
America/St_Vincent
America/Thule
America/Tortola
America/Virgin
Antarctica/Palmer
Atlantic/Bermuda
Atlantic/Stanley
Brazil/West
Canada/Atlantic
Chile/Continental
PRT
SystemV/AST4
SystemV/AST4ADT


GMT-5:00 :
America/Bogota
America/Cayman
America/Detroit
America/Eirunepe
America/Fort_Wayne
America/Grand_Turk
America/Guayaquil
America/Havana
America/Indiana/Indianapolis
America/Indiana/Knox
America/Indiana/Marengo
America/Indiana/Vevay
America/Indianapolis
America/Iqaluit
America/Jamaica
America/Kentucky/Louisville
America/Kentucky/Monticello
America/Knox_IN
America/Lima
America/Louisville
America/Montreal
America/Nassau
America/New_York
America/Nipigon
America/Panama
America/Pangnirtung
America/Port-au-Prince
America/Porto_Acre
America/Rio_Branco
America/Thunder_Bay
Brazil/Acre
Canada/Eastern
Cuba
EST
EST5EDT
IET
Jamaica
SystemV/EST5
SystemV/EST5EDT
US/East-Indiana
US/Eastern
US/Indiana-Starke
US/Michigan



GMT-6:00 :
America/Belize
America/Cancun
America/Chicago
America/Costa_Rica
America/El_Salvador
America/Guatemala
America/Managua
America/Menominee
America/Merida
America/Mexico_City
America/Monterrey
America/North_Dakota/Center
America/Rainy_River
America/Rankin_Inlet
America/Regina
America/Swift_Current
America/Tegucigalpa
America/Winnipeg
CST
CST6CDT
Canada/Central
Canada/East-Saskatchewan
Canada/Saskatchewan
Chile/EasterIsland
Mexico/General
Pacific/Easter
Pacific/Galapagos
SystemV/CST6
SystemV/CST6CDT
US/Central


GMT-7:00 :
America/Boise
America/Cambridge_Bay
America/Chihuahua
America/Dawson_Creek
America/Denver
America/Edmonton
America/Hermosillo
America/Inuvik
America/Mazatlan
America/Phoenix
America/Shiprock
America/Yellowknife
Canada/Mountain
MST
MST7MDT
Mexico/BajaSur
Navajo
PNT
SystemV/MST7
SystemV/MST7MDT
US/Arizona
US/Mountain


GMT-8:00 :
America/Dawson
America/Ensenada
America/Los_Angeles
America/Tijuana
America/Vancouver
America/Whitehorse
Canada/Pacific
Canada/Yukon
Mexico/BajaNorte
PST
PST8PDT
Pacific/Pitcairn
SystemV/PST8
SystemV/PST8PDT
US/Pacific
US/Pacific-New

GMT-9:00 :
AST
America/Anchorage
America/Juneau
America/Nome
America/Yakutat
Pacific/Gambier
SystemV/YST9
SystemV/YST9YDT
US/Alaska


GMT-9:30 :
Pacific/Marquesas


GMT-10:00 :
America/Adak
America/Atka
HST
Pacific/Fakaofo
Pacific/Honolulu
Pacific/Johnston
Pacific/Rarotonga
Pacific/Tahiti
SystemV/HST10
US/Aleutian
US/Hawaii



GMT-11:00 :
MIT
Pacific/Apia
Pacific/Midway
Pacific/Niue
Pacific/Pago_Pago
Pacific/Samoa
US/Samoa

(to be continued)

(continued)

GMT+1:00 :
Africa/Algiers
Africa/Bangui
Africa/Brazzaville
Africa/Ceuta
Africa/Douala
Africa/Kinshasa
Africa/Lagos
Africa/Libreville
Africa/Luanda
Africa/Malabo
Africa/Ndjamena
Africa/Niamey
Africa/Porto-Novo
Africa/Tunis
Africa/Windhoek
Arctic/Longyearbyen
Atlantic/Jan_Mayen
CET
ECT
Europe/Amsterdam
Europe/Andorra
Europe/Belgrade
Europe/Berlin
Europe/Bratislava
Europe/Brussels
Europe/Budapest
Europe/Copenhagen
Europe/Gibraltar
Europe/Ljubljana
Europe/Luxembourg
Europe/Madrid
Europe/Malta
Europe/Monaco
Europe/Oslo
Europe/Paris
Europe/Prague
Europe/Rome
Europe/San_Marino
Europe/Sarajevo
Europe/Skopje
Europe/Stockholm
Europe/Tirane
Europe/Vaduz
Europe/Vatican
Europe/Vienna
Europe/Warsaw
Europe/Zagreb
Europe/Zurich
MET
Poland


GMT+2:00 :
ART
Africa/Blantyre
Africa/Bujumbura
Africa/Cairo
Africa/Gaborone
Africa/Harare
Africa/Johannesburg
Africa/Kigali
Africa/Lubumbashi
Africa/Lusaka
Africa/Maputo
Africa/Maseru
Africa/Mbabane
Africa/Tripoli
Asia/Amman
Asia/Beirut
Asia/Damascus
Asia/Gaza
Asia/Istanbul
Asia/Jerusalem
Asia/Nicosia
Asia/Tel_Aviv
CAT
EET
Egypt
Europe/Athens
Europe/Bucharest
Europe/Chisinau
Europe/Helsinki
Europe/Istanbul
Europe/Kaliningrad
Europe/Kiev
Europe/Minsk
Europe/Nicosia
Europe/Riga
Europe/Simferopol
Europe/Sofia
Europe/Tallinn
Europe/Tiraspol
Europe/Uzhgorod
Europe/Vilnius
Europe/Zaporozhye
Israel
Libya
Turkey



GMT+3:00 :
Africa/Addis_Ababa
Africa/Asmera
Africa/Dar_es_Salaam
Africa/Djibouti
Africa/Kampala
Africa/Khartoum
Africa/Mogadishu
Africa/Nairobi
Antarctica/Syowa
Asia/Aden
Asia/Baghdad
Asia/Bahrain
Asia/Kuwait
Asia/Qatar
Asia/Riyadh
EAT
Europe/Moscow
Indian/Antananarivo
Indian/Comoro
Indian/Mayotte
W-SU


GMT+3:30 :
Asia/Tehran
Iran


GMT+4:00 :
Asia/Aqtau
Asia/Baku
Asia/Dubai
Asia/Muscat
Asia/Oral
Asia/Tbilisi
Asia/Yerevan
Europe/Samara
Indian/Mahe
Indian/Mauritius
Indian/Reunion
NET



GMT+4:30 :
Asia/Kabul



GMT+5:00 :
Asia/Aqtobe
Asia/Ashgabat
Asia/Ashkhabad
Asia/Bishkek
Asia/Dushanbe
Asia/Karachi
Asia/Samarkand
Asia/Tashkent
Asia/Yekaterinburg
Indian/Kerguelen
Indian/Maldives
PLT



GMT+5:30:
Asia/Calcutta
IST

GMT+5:45 :
Asia/Katmandu

GMT+6:00 :
Antarctica/Mawson
Antarctica/Vostok
Asia/Almaty
Asia/Colombo
Asia/Dacca
Asia/Dhaka
Asia/Novosibirsk
Asia/Omsk
Asia/Qyzylorda
Asia/Thimbu
Asia/Thimphu
BST
Indian/Chagos


GMT+6:30 :
Asia/Rangoon
Indian/Cocos


GMT+7:00 :
Antarctica/Davis
Asia/Bangkok
Asia/Hovd
Asia/Jakarta
Asia/Krasnoyarsk
Asia/Phnom_Penh
Asia/Pontianak
Asia/Saigon
Asia/Vientiane
Indian/Christmas
VST


GMT+8:00 :
Antarctica/Casey
Asia/Brunei
Asia/Chongqing
Asia/Chungking
Asia/Harbin
Asia/Hong_Kong
Asia/Irkutsk
Asia/Kashgar
Asia/Kuala_Lumpur
Asia/Kuching
Asia/Macao
Asia/Macau
Asia/Makassar
Asia/Manila
Asia/Shanghai
Asia/Singapore
Asia/Taipei
Asia/Ujung_Pandang
Asia/Ulaanbaatar
Asia/Ulan_Bator
Asia/Urumqi
Australia/Perth
Australia/West
CTT
Hongkong
PRC
Singapore



GMT+9:00 :
Asia/Choibalsan
Asia/Dili
Asia/Jayapura
Asia/Pyongyang
Asia/Seoul
Asia/Tokyo
Asia/Yakutsk
JST
Japan
Pacific/Palau
ROK


GMT+9:30 :
ACT
Australia/Adelaide
Australia/Broken_Hill
Australia/Darwin
Australia/North
Australia/South
Australia/Yancowinna


GMT+10:00 :
AET
Antarctica/DumontDUrville
Asia/Sakhalin
Asia/Vladivostok
Australia/ACT
Australia/Brisbane
Australia/Canberra
Australia/Hobart
Australia/Lindeman
Australia/Melbourne
Australia/NSW
Australia/Queensland
Australia/Sydney
Australia/Tasmania
Australia/Victoria
Pacific/Guam
Pacific/Port_Moresby
Pacific/Saipan
Pacific/Truk
Pacific/Yap


GMT+10:30 :
Australia/LHI
Australia/Lord_Howe



GMT+11:00 :
Asia/Magadan
Pacific/Efate
Pacific/Guadalcanal
Pacific/Kosrae
Pacific/Noumea
Pacific/Ponape
SST


GMT+11:30 :
Pacific/Norfolk

(Completed.)

Holy cow, Sat_f, You must have a whole lot of time to kill. LOL c.i.

c.i. ..
The result above was one of the simplest things for the langage Java, though DST(Dalight Daving Time)'s will be slightly more complicated as Craven de Kere said above. Those timezones within the same Standard Time offset range (e.g., "GMT-8") can have different rules for DST among them. When someone needed DST offset around March/April, let me know, I would try it.

satt,

Do you work in web development or programming?

Craven de Kere..
Actually, I am in the field of math and use programming language, not a web developer.

satt_f, I wasn't aware of the .30 and .15 minute difference in the India and Nepal time zones until my travel there two years ago. It's really amusing to realize how really complicated the time zones can be. c.i.

c.i. ..
India to Nepal, in which offset difference is subtle and delicate, but from Nepal to Tibet, it might be more gross with almost the same longitude.


It would be a good challenge to write a code for every possible DST offset.

I read this and had to see what on earth was being discussed. <We prefer the subtle & delicate, please.> Fine talk about time zones.

Greeting satt_focusable, nice to have a mathematician with us. 15 & 30 minute intervals? I wonder what "actual" time I would use if my governmental authorities sanctioned those intervals?

CI, You and I are on the same Pacific Coast time, but should you be ahead by 15 or 30 or even 45 minutes from me? I am 'most directly south of Seattle, just a hairline fracture west, following the curve of the earth <I have just checked a globe.> We are further to the west of 120 degrees than the leading edge of LA. You must be ahead... but how far? It looks like it could be 30 minutes! Have I been robbed, or have you?

satt,

DST offset is one thing, when it's activated is another. DST coding is hapmered because the day that DST starts in many areas changes from year to year.

It would have to be synconized with a time server that has all of this info updated every year or these updates would have to be done manually.

A challenge indeed!

What I have planned is a bit more simple. It would just be a box that the user checks to offset their time. A more complicated one is just vapor ware for now.

Craven, "Vapor ware?" c.i.

Piffka, I looked at my map, and I see 130 degrees longitude between our time zones, but both live in PST. Actually, for me, anyway, a 30 min or 1 hour difference doesn't make any difference one way or another. I live by daylight and the t.v.. c.i.

Four minitutes per degree in longitude.
For example, between Los Angeles, CA (118.23) and San Francisco, CA (122.43) the physical time offset is about 16.8 minutes.

Craven..
I would not be bothered with DST's if you should think it is a part of your task, though I could offer some help about it.

satt_f, Thanks for that education on time. I visited Greenwich many, many, years ago, and I'm sure it was 'mentioned' there someplace, but have forgotten everything about it. c.i.