How to know what time it is

I've been working on a world clock over the past week and I've finally got it to the point where I feel like I can release it. Sample runs follow and the source is linked to above:

 % ../sqlTime 
Africa/Abidjan, 00:00:00
Africa/Accra, 00:00:00
Africa/Addis_Ababa, 03:00:00
Africa/Algiers, 01:00:00
Africa/Asmara, 03:00:00
Africa/Asmera, 03:00:00
Africa/Bamako, 00:00:00
Africa/Bangui, 01:00:00
Africa/Banjul, 00:00:00
Africa/Bissau, 00:00:00
Africa/Blantyre, 02:00:00
Africa/Brazzaville, 01:00:00
Africa/Bujumbura, 02:00:00
Africa/Cairo, 02:00:00
Africa/Casablanca, 01:00:00
Africa/Ceuta, 01:00:00
Africa/Conakry, 00:00:00
Africa/Dakar, 00:00:00
Africa/Dar_es_Salaam, 03:00:00
Africa/Djibouti, 03:00:00
Africa/Douala, 01:00:00
Africa/El_Aaiun, 01:00:00
Africa/Freetown, 00:00:00
Africa/Gaborone, 02:00:00
Africa/Harare, 02:00:00
Africa/Johannesburg, 02:00:00
Africa/Juba, 03:00:00
Africa/Kampala, 03:00:00
Africa/Khartoum, 02:00:00
Africa/Kigali, 02:00:00
Africa/Kinshasa, 01:00:00
Africa/Lagos, 01:00:00
Africa/Libreville, 01:00:00
Africa/Lome, 00:00:00
Africa/Luanda, 01:00:00
Africa/Lubumbashi, 02:00:00
Africa/Lusaka, 02:00:00
Africa/Malabo, 01:00:00
Africa/Maputo, 02:00:00
Africa/Maseru, 02:00:00
Africa/Mbabane, 02:00:00
Africa/Mogadishu, 03:00:00
Africa/Monrovia, 00:00:00
Africa/Nairobi, 03:00:00
Africa/Ndjamena, 01:00:00
Africa/Niamey, 01:00:00
Africa/Nouakchott, 00:00:00
Africa/Ouagadougou, 00:00:00
Africa/Porto-Novo, 01:00:00
Africa/Sao_Tome, 01:00:00
Africa/Timbuktu, 00:00:00
Africa/Tripoli, 02:00:00
Africa/Tunis, 01:00:00
Africa/Windhoek, 02:00:00
America/Adak, -10:00:00
America/Anchorage, -09:00:00
America/Anguilla, -04:00:00
America/Antigua, -04:00:00
America/Araguaina, -03:00:00
America/Argentina/Buenos_Aires, -03:00:00
America/Argentina/Catamarca, -03:00:00
America/Argentina/ComodRivadavia, -03:00:00
America/Argentina/Cordoba, -03:00:00
America/Argentina/Jujuy, -03:00:00
America/Argentina/La_Rioja, -03:00:00
America/Argentina/Mendoza, -03:00:00
America/Argentina/Rio_Gallegos, -03:00:00
America/Argentina/Salta, -03:00:00
America/Argentina/San_Juan, -03:00:00
America/Argentina/San_Luis, -03:00:00
America/Argentina/Tucuman, -03:00:00
America/Argentina/Ushuaia, -03:00:00
America/Aruba, -04:00:00
America/Asuncion, -03:00:00
America/Atikokan, -05:00:00
America/Atka, -10:00:00
America/Bahia, -03:00:00
America/Bahia_Banderas, -06:00:00
America/Barbados, -04:00:00
America/Belem, -03:00:00
America/Belize, -06:00:00
America/Blanc-Sablon, -04:00:00
America/Boa_Vista, -04:00:00
America/Bogota, -05:00:00
America/Boise, -07:00:00
America/Buenos_Aires, -03:00:00
America/Cambridge_Bay, -07:00:00
America/Campo_Grande, -03:00:00
America/Cancun, -05:00:00
America/Caracas, -04:00:00
America/Catamarca, -03:00:00
America/Cayenne, -03:00:00
America/Cayman, -05:00:00
America/Chicago, -06:00:00
America/Chihuahua, -07:00:00
America/Coral_Harbour, -05:00:00
America/Cordoba, -03:00:00
America/Costa_Rica, -06:00:00
America/Creston, -07:00:00
America/Cuiaba, -03:00:00
America/Curacao, -04:00:00
America/Danmarkshavn, 00:00:00
America/Dawson, -08:00:00
America/Dawson_Creek, -07:00:00
America/Denver, -07:00:00
America/Detroit, -05:00:00
America/Dominica, -04:00:00
America/Edmonton, -07:00:00
America/Eirunepe, -05:00:00
America/El_Salvador, -06:00:00
America/Ensenada, -08:00:00
America/Fort_Nelson, -07:00:00
America/Fort_Wayne, -05:00:00
America/Fortaleza, -03:00:00
America/Glace_Bay, -04:00:00
America/Godthab, -03:00:00
America/Goose_Bay, -04:00:00
America/Grand_Turk, -05:00:00
America/Grenada, -04:00:00
America/Guadeloupe, -04:00:00
America/Guatemala, -06:00:00
America/Guayaquil, -05:00:00
America/Guyana, -04:00:00
America/Halifax, -04:00:00
America/Havana, -05:00:00
America/Hermosillo, -07:00:00
America/Indiana/Indianapolis, -05:00:00
America/Indiana/Knox, -06:00:00
America/Indiana/Marengo, -05:00:00
America/Indiana/Petersburg, -05:00:00
America/Indiana/Tell_City, -06:00:00
America/Indiana/Vevay, -05:00:00
America/Indiana/Vincennes, -05:00:00
America/Indiana/Winamac, -05:00:00
America/Indianapolis, -05:00:00
America/Inuvik, -07:00:00
America/Iqaluit, -05:00:00
America/Jamaica, -05:00:00
America/Jujuy, -03:00:00
America/Juneau, -09:00:00
America/Kentucky/Louisville, -05:00:00
America/Kentucky/Monticello, -05:00:00
America/Knox_IN, -06:00:00
America/Kralendijk, -04:00:00
America/La_Paz, -04:00:00
America/Lima, -05:00:00
America/Los_Angeles, -08:00:00
America/Louisville, -05:00:00
America/Lower_Princes, -04:00:00
America/Maceio, -03:00:00
America/Managua, -06:00:00
America/Manaus, -04:00:00
America/Marigot, -04:00:00
America/Martinique, -04:00:00
America/Matamoros, -06:00:00
America/Mazatlan, -07:00:00
America/Mendoza, -03:00:00
America/Menominee, -06:00:00
America/Merida, -06:00:00
America/Metlakatla, -09:00:00
America/Mexico_City, -06:00:00
America/Miquelon, -03:00:00
America/Moncton, -04:00:00
America/Monterrey, -06:00:00
America/Montevideo, -03:00:00
America/Montreal, -05:00:00
America/Montserrat, -04:00:00
America/Nassau, -05:00:00
America/New_York, -05:00:00
America/Nipigon, -05:00:00
America/Nome, -09:00:00
America/Noronha, -02:00:00
America/North_Dakota/Beulah, -06:00:00
America/North_Dakota/Center, -06:00:00
America/North_Dakota/New_Salem, -06:00:00
America/Ojinaga, -07:00:00
America/Panama, -05:00:00
America/Pangnirtung, -05:00:00
America/Paramaribo, -03:00:00
America/Phoenix, -07:00:00
America/Port-au-Prince, -05:00:00
America/Port_of_Spain, -04:00:00
America/Porto_Acre, -05:00:00
America/Porto_Velho, -04:00:00
America/Puerto_Rico, -04:00:00
America/Punta_Arenas, -03:00:00
America/Rainy_River, -06:00:00
America/Rankin_Inlet, -06:00:00
America/Recife, -03:00:00
America/Regina, -06:00:00
America/Resolute, -06:00:00
America/Rio_Branco, -05:00:00
America/Rosario, -03:00:00
America/Santa_Isabel, -08:00:00
America/Santarem, -03:00:00
America/Santiago, -03:00:00
America/Santo_Domingo, -04:00:00
America/Sao_Paulo, -02:00:00
America/Scoresbysund, -01:00:00
America/Shiprock, -07:00:00
America/Sitka, -09:00:00
America/St_Barthelemy, -04:00:00
America/St_Johns, -03:30:00
America/St_Kitts, -04:00:00
America/St_Lucia, -04:00:00
America/St_Thomas, -04:00:00
America/St_Vincent, -04:00:00
America/Swift_Current, -06:00:00
America/Tegucigalpa, -06:00:00
America/Thule, -04:00:00
America/Thunder_Bay, -05:00:00
America/Tijuana, -08:00:00
America/Toronto, -05:00:00
America/Tortola, -04:00:00
America/Vancouver, -08:00:00
America/Virgin, -04:00:00
America/Whitehorse, -08:00:00
America/Winnipeg, -06:00:00
America/Yakutat, -09:00:00
America/Yellowknife, -07:00:00
Antarctica/Casey, 08:00:00
Antarctica/Davis, 07:00:00
Antarctica/DumontDUrville, 10:00:00
Antarctica/Macquarie, 11:00:00
Antarctica/Mawson, 05:00:00
Antarctica/McMurdo, 13:00:00
Antarctica/Palmer, -03:00:00
Antarctica/Rothera, -03:00:00
Antarctica/South_Pole, 13:00:00
Antarctica/Syowa, 03:00:00
Antarctica/Troll, 00:00:00
Antarctica/Vostok, 06:00:00
Arctic/Longyearbyen, 01:00:00
Asia/Aden, 03:00:00
Asia/Almaty, 06:00:00
Asia/Amman, 02:00:00
Asia/Anadyr, 12:00:00
Asia/Aqtau, 05:00:00
Asia/Aqtobe, 05:00:00
Asia/Ashgabat, 05:00:00
Asia/Ashkhabad, 05:00:00
Asia/Atyrau, 05:00:00
Asia/Baghdad, 03:00:00
Asia/Bahrain, 03:00:00
Asia/Baku, 04:00:00
Asia/Bangkok, 07:00:00
Asia/Barnaul, 07:00:00
Asia/Beirut, 02:00:00
Asia/Bishkek, 06:00:00
Asia/Brunei, 08:00:00
Asia/Calcutta, 05:30:00
Asia/Chita, 09:00:00
Asia/Choibalsan, 08:00:00
Asia/Chongqing, 08:00:00
Asia/Chungking, 08:00:00
Asia/Colombo, 05:30:00
Asia/Dacca, 06:00:00
Asia/Damascus, 02:00:00
Asia/Dhaka, 06:00:00
Asia/Dili, 09:00:00
Asia/Dubai, 04:00:00
Asia/Dushanbe, 05:00:00
Asia/Famagusta, 02:00:00
Asia/Gaza, 02:00:00
Asia/Harbin, 08:00:00
Asia/Hebron, 02:00:00
Asia/Ho_Chi_Minh, 07:00:00
Asia/Hong_Kong, 08:00:00
Asia/Hovd, 07:00:00
Asia/Irkutsk, 08:00:00
Asia/Istanbul, 03:00:00
Asia/Jakarta, 07:00:00
Asia/Jayapura, 09:00:00
Asia/Jerusalem, 02:00:00
Asia/Kabul, 04:30:00
Asia/Kamchatka, 12:00:00
Asia/Karachi, 05:00:00
Asia/Kashgar, 06:00:00
Asia/Kathmandu, 05:45:00
Asia/Katmandu, 05:45:00
Asia/Khandyga, 09:00:00
Asia/Kolkata, 05:30:00
Asia/Krasnoyarsk, 07:00:00
Asia/Kuala_Lumpur, 08:00:00
Asia/Kuching, 08:00:00
Asia/Kuwait, 03:00:00
Asia/Macao, 08:00:00
Asia/Macau, 08:00:00
Asia/Magadan, 11:00:00
Asia/Makassar, 08:00:00
Asia/Manila, 08:00:00
Asia/Muscat, 04:00:00
Asia/Nicosia, 02:00:00
Asia/Novokuznetsk, 07:00:00
Asia/Novosibirsk, 07:00:00
Asia/Omsk, 06:00:00
Asia/Oral, 05:00:00
Asia/Phnom_Penh, 07:00:00
Asia/Pontianak, 07:00:00
Asia/Pyongyang, 09:00:00
Asia/Qatar, 03:00:00
Asia/Qyzylorda, 06:00:00
Asia/Rangoon, 06:30:00
Asia/Riyadh, 03:00:00
Asia/Saigon, 07:00:00
Asia/Sakhalin, 11:00:00
Asia/Samarkand, 05:00:00
Asia/Seoul, 09:00:00
Asia/Shanghai, 08:00:00
Asia/Singapore, 08:00:00
Asia/Srednekolymsk, 11:00:00
Asia/Taipei, 08:00:00
Asia/Tashkent, 05:00:00
Asia/Tbilisi, 04:00:00
Asia/Tehran, 03:30:00
Asia/Tel_Aviv, 02:00:00
Asia/Thimbu, 06:00:00
Asia/Thimphu, 06:00:00
Asia/Tokyo, 09:00:00
Asia/Tomsk, 07:00:00
Asia/Ujung_Pandang, 08:00:00
Asia/Ulaanbaatar, 08:00:00
Asia/Ulan_Bator, 08:00:00
Asia/Urumqi, 06:00:00
Asia/Ust-Nera, 10:00:00
Asia/Vientiane, 07:00:00
Asia/Vladivostok, 10:00:00
Asia/Yakutsk, 09:00:00
Asia/Yangon, 06:30:00
Asia/Yekaterinburg, 05:00:00
Asia/Yerevan, 04:00:00
Atlantic/Azores, -01:00:00
Atlantic/Bermuda, -04:00:00
Atlantic/Canary, 00:00:00
Atlantic/Cape_Verde, -01:00:00
Atlantic/Faeroe, 00:00:00
Atlantic/Faroe, 00:00:00
Atlantic/Jan_Mayen, 01:00:00
Atlantic/Madeira, 00:00:00
Atlantic/Reykjavik, 00:00:00
Atlantic/South_Georgia, -02:00:00
Atlantic/St_Helena, 00:00:00
Atlantic/Stanley, -03:00:00
Australia/ACT, 11:00:00
Australia/Adelaide, 10:30:00
Australia/Brisbane, 10:00:00
Australia/Broken_Hill, 10:30:00
Australia/Canberra, 11:00:00
Australia/Currie, 11:00:00
Australia/Darwin, 09:30:00
Australia/Eucla, 08:45:00
Australia/Hobart, 11:00:00
Australia/LHI, 11:00:00
Australia/Lindeman, 10:00:00
Australia/Lord_Howe, 11:00:00
Australia/Melbourne, 11:00:00
Australia/NSW, 11:00:00
Australia/North, 09:30:00
Australia/Perth, 08:00:00
Australia/Queensland, 10:00:00
Australia/South, 10:30:00
Australia/Sydney, 11:00:00
Australia/Tasmania, 11:00:00
Australia/Victoria, 11:00:00
Australia/West, 08:00:00
Australia/Yancowinna, 10:30:00
Brazil/Acre, -05:00:00
Brazil/DeNoronha, -02:00:00
Brazil/East, -02:00:00
Brazil/West, -04:00:00
CST6CDT, -06:00:00
Canada/Atlantic, -04:00:00
Canada/Central, -06:00:00
Canada/Eastern, -05:00:00
Canada/Mountain, -07:00:00
Canada/Newfoundland, -03:30:00
Canada/Pacific, -08:00:00
Canada/Saskatchewan, -06:00:00
Canada/Yukon, -08:00:00
Chile/Continental, -03:00:00
Chile/EasterIsland, -05:00:00
EST5EDT, -05:00:00
Egypt, 02:00:00
Etc/GMT, 00:00:00
Etc/GMT+0, 00:00:00
Etc/GMT+1, -01:00:00
Etc/GMT+10, -10:00:00
Etc/GMT+11, -11:00:00
Etc/GMT+12, -12:00:00
Etc/GMT+2, -02:00:00
Etc/GMT+3, -03:00:00
Etc/GMT+4, -04:00:00
Etc/GMT+5, -05:00:00
Etc/GMT+6, -06:00:00
Etc/GMT+7, -07:00:00
Etc/GMT+8, -08:00:00
Etc/GMT+9, -09:00:00
Etc/GMT-0, 00:00:00
Etc/GMT-1, 01:00:00
Etc/GMT-10, 10:00:00
Etc/GMT-11, 11:00:00
Etc/GMT-12, 12:00:00
Etc/GMT-13, 13:00:00
Etc/GMT-14, 14:00:00
Etc/GMT-2, 02:00:00
Etc/GMT-3, 03:00:00
Etc/GMT-4, 04:00:00
Etc/GMT-5, 05:00:00
Etc/GMT-6, 06:00:00
Etc/GMT-7, 07:00:00
Etc/GMT-8, 08:00:00
Etc/GMT-9, 09:00:00
Etc/GMT0, 00:00:00
Etc/Greenwich, 00:00:00
Etc/UCT, 00:00:00
Etc/UTC, 00:00:00
Etc/Universal, 00:00:00
Etc/Zulu, 00:00:00
Europe/Amsterdam, 01:00:00
Europe/Andorra, 01:00:00
Europe/Astrakhan, 04:00:00
Europe/Athens, 02:00:00
Europe/Belfast, 00:00:00
Europe/Belgrade, 01:00:00
Europe/Berlin, 01:00:00
Europe/Bratislava, 01:00:00
Europe/Brussels, 01:00:00
Europe/Bucharest, 02:00:00
Europe/Budapest, 01:00:00
Europe/Busingen, 01:00:00
Europe/Chisinau, 02:00:00
Europe/Copenhagen, 01:00:00
Europe/Dublin, 00:00:00
Europe/Gibraltar, 01:00:00
Europe/Guernsey, 00:00:00
Europe/Helsinki, 02:00:00
Europe/Isle_of_Man, 00:00:00
Europe/Istanbul, 03:00:00
Europe/Jersey, 00:00:00
Europe/Kaliningrad, 02:00:00
Europe/Kiev, 02:00:00
Europe/Kirov, 03:00:00
Europe/Lisbon, 00:00:00
Europe/Ljubljana, 01:00:00
Europe/London, 00:00:00
Europe/Luxembourg, 01:00:00
Europe/Madrid, 01:00:00
Europe/Malta, 01:00:00
Europe/Mariehamn, 02:00:00
Europe/Minsk, 03:00:00
Europe/Monaco, 01:00:00
Europe/Moscow, 03:00:00
Europe/Nicosia, 02:00:00
Europe/Oslo, 01:00:00
Europe/Paris, 01:00:00
Europe/Podgorica, 01:00:00
Europe/Prague, 01:00:00
Europe/Riga, 02:00:00
Europe/Rome, 01:00:00
Europe/Samara, 04:00:00
Europe/San_Marino, 01:00:00
Europe/Sarajevo, 01:00:00
Europe/Saratov, 04:00:00
Europe/Simferopol, 03:00:00
Europe/Skopje, 01:00:00
Europe/Sofia, 02:00:00
Europe/Stockholm, 01:00:00
Europe/Tallinn, 02:00:00
Europe/Tirane, 01:00:00
Europe/Tiraspol, 02:00:00
Europe/Ulyanovsk, 04:00:00
Europe/Uzhgorod, 02:00:00
Europe/Vaduz, 01:00:00
Europe/Vatican, 01:00:00
Europe/Vienna, 01:00:00
Europe/Vilnius, 02:00:00
Europe/Volgograd, 04:00:00
Europe/Warsaw, 01:00:00
Europe/Zagreb, 01:00:00
Europe/Zaporozhye, 02:00:00
Europe/Zurich, 01:00:00
GB-Eire, 00:00:00
GMT+0, 00:00:00
GMT-0, 00:00:00
Greenwich, 00:00:00
Hongkong, 08:00:00
Iceland, 00:00:00
Indian/Antananarivo, 03:00:00
Indian/Chagos, 06:00:00
Indian/Christmas, 07:00:00
Indian/Cocos, 06:30:00
Indian/Comoro, 03:00:00
Indian/Kerguelen, 05:00:00
Indian/Mahe, 04:00:00
Indian/Maldives, 05:00:00
Indian/Mauritius, 04:00:00
Indian/Mayotte, 03:00:00
Indian/Reunion, 04:00:00
Israel, 02:00:00
Jamaica, -05:00:00
Japan, 09:00:00
Kwajalein, 12:00:00
Libya, 02:00:00
MST7MDT, -07:00:00
Mexico/BajaNorte, -08:00:00
Mexico/BajaSur, -07:00:00
Mexico/General, -06:00:00
NZ-CHAT, 13:45:00
Navajo, -07:00:00
PST8PDT, -08:00:00
Pacific/Apia, 14:00:00
Pacific/Auckland, 13:00:00
Pacific/Bougainville, 11:00:00
Pacific/Chatham, 13:45:00
Pacific/Chuuk, 10:00:00
Pacific/Easter, -05:00:00
Pacific/Efate, 11:00:00
Pacific/Enderbury, 13:00:00
Pacific/Fakaofo, 13:00:00
Pacific/Fiji, 12:00:00
Pacific/Funafuti, 12:00:00
Pacific/Galapagos, -06:00:00
Pacific/Gambier, -09:00:00
Pacific/Guadalcanal, 11:00:00
Pacific/Guam, 10:00:00
Pacific/Honolulu, -10:00:00
Pacific/Johnston, -10:00:00
Pacific/Kiritimati, 14:00:00
Pacific/Kosrae, 11:00:00
Pacific/Kwajalein, 12:00:00
Pacific/Majuro, 12:00:00
Pacific/Marquesas, -09:30:00
Pacific/Midway, -11:00:00
Pacific/Nauru, 12:00:00
Pacific/Niue, -11:00:00
Pacific/Norfolk, 11:00:00
Pacific/Noumea, 11:00:00
Pacific/Pago_Pago, -11:00:00
Pacific/Palau, 09:00:00
Pacific/Pitcairn, -08:00:00
Pacific/Pohnpei, 11:00:00
Pacific/Ponape, 11:00:00
Pacific/Port_Moresby, 10:00:00
Pacific/Rarotonga, -10:00:00
Pacific/Saipan, 10:00:00
Pacific/Samoa, -11:00:00
Pacific/Tahiti, -10:00:00
Pacific/Tarawa, 12:00:00
Pacific/Tongatapu, 13:00:00
Pacific/Truk, 10:00:00
Pacific/Wake, 12:00:00
Pacific/Wallis, 12:00:00
Pacific/Yap, 10:00:00
Poland, 01:00:00
Portugal, 00:00:00
Singapore, 08:00:00
Turkey, 03:00:00
US/Alaska, -09:00:00
US/Aleutian, -10:00:00
US/Arizona, -07:00:00
US/Central, -06:00:00
US/East-Indiana, -05:00:00
US/Eastern, -05:00:00
US/Hawaii, -10:00:00
US/Indiana-Starke, -06:00:00
US/Michigan, -05:00:00
US/Mountain, -07:00:00
US/Pacific, -08:00:00
US/Samoa, -11:00:00
Universal, 00:00:00
posixrules, -05:00:00

% ../sqlTime CSTa
Invalid timezone CSTa

% ../sqlTime Europe/Madrid
2019-01-15 10:00:50.570864

In other words, ¡hola España!