Quick example where we (1) load a list of locales from json, and (2) print out the time now in those locales.

listtz.go

// Get list of timezones from ftp://munnari.oz.au/pub/oldtz/
// ftp://munnari.oz.au/pub/oldtz/tzdata2018d.tar.gz

// Locale entries must exist in:
// go/1.10.3/libexec/lib/time/zoneinfo.zip

package main

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"log"
	"os"
	"time"
)

type tzlist map[string]string

func must(err error) {
	if err != nil {
		log.Fatal(err)
	}
}

func getLocalTime(loc string) time.Time {
	locale, err := time.LoadLocation(loc)
	if err != nil {
		log.Println(err)
	}
	return time.Now().In(locale)
}

func loadtzList() tzlist {
	var t tzlist
	var j []byte
	file, err := os.Open("tz.json")
	must(err)
	defer file.Close()
	j, err = ioutil.ReadAll(file)
	must(err)
	err = json.Unmarshal(j, &t)
	must(err)
	return t
}

func main() {
	list := loadtzList()
	for _, v := range list {
		fmt.Printf("%s: %v\n", v, getLocalTime(list[v]).Format("Mon, 02 Jan 2006 03:04 PM MST")) // use something close to RFC 1123 (Mon, 02 Jan 2006 15:04:05 MST)
	}
}

tz.json

{
  "Africa/Abidjan":"Africa/Abidjan",
  "Africa/Accra":"Africa/Accra",
  "Africa/Algiers":"Africa/Algiers",
  "Africa/Bissau":"Africa/Bissau",
  "Africa/Cairo":"Africa/Cairo",
  "Africa/Casablanca":"Africa/Casablanca",
  "Africa/Ceuta":"Africa/Ceuta",
  "Africa/El_Aaiun":"Africa/El Aaiun",
  "Africa/Johannesburg":"Africa/Johannesburg",
  "Africa/Juba":"Africa/Juba",
  "Africa/Khartoum":"Africa/Khartoum",
  "Africa/Lagos":"Africa/Lagos",
  "Africa/Maputo":"Africa/Maputo",
  "Africa/Monrovia":"Africa/Monrovia",
  "Africa/Nairobi":"Africa/Nairobi",
  "Africa/Ndjamena":"Africa/Ndjamena",
  "Africa/Sao_Tome":"Africa/Sao Tome",
  "Africa/Tripoli":"Africa/Tripoli",
  "Africa/Tunis":"Africa/Tunis",
  "Africa/Windhoek":"Africa/Windhoek",
  "America/Adak":"America/Adak",
  "America/Anchorage":"America/Anchorage",
  "America/Araguaina":"America/Araguaina",
  "America/Argentina/Buenos_Aires":"America/Argentina/Buenos Aires",
  "America/Argentina/Catamarca":"America/Argentina/Catamarca",
  "America/Argentina/Cordoba":"America/Argentina/Cordoba",
  "America/Argentina/Jujuy":"America/Argentina/Jujuy",
  "America/Argentina/La_Rioja":"America/Argentina/La Rioja",
  "America/Argentina/Mendoza":"America/Argentina/Mendoza",
  "America/Argentina/Rio_Gallegos":"America/Argentina/Rio Gallegos",
  "America/Argentina/Salta":"America/Argentina/Salta",
  "America/Argentina/San_Juan":"America/Argentina/San Juan",
  "America/Argentina/San_Luis":"America/Argentina/San Luis",
  "America/Argentina/Tucuman":"America/Argentina/Tucuman",
  "America/Argentina/Ushuaia":"America/Argentina/Ushuaia",
  "America/Asuncion":"America/Asuncion",
  "America/Atikokan":"America/Atikokan",
  "America/Bahia":"America/Bahia",
  "America/Bahia_Banderas":"America/Bahia Banderas",
  "America/Barbados":"America/Barbados",
  "America/Belem":"America/Belem",
  "America/Belize":"America/Belize",
  "America/Blanc-Sablon":"America/Blanc-Sablon",
  "America/Boa_Vista":"America/Boa Vista",
  "America/Bogota":"America/Bogota",
  "America/Boise":"America/Boise",
  "America/Cambridge_Bay":"America/Cambridge Bay",
  "America/Campo_Grande":"America/Campo Grande",
  "America/Cancun":"America/Cancun",
  "America/Caracas":"America/Caracas",
  "America/Cayenne":"America/Cayenne",
  "America/Chicago":"America/Chicago",
  "America/Chihuahua":"America/Chihuahua",
  "America/Costa_Rica":"America/Costa Rica",
  "America/Creston":"America/Creston",
  "America/Cuiaba":"America/Cuiaba",
  "America/Curacao":"America/Curacao",
  "America/Danmarkshavn":"America/Danmarkshavn",
  "America/Dawson":"America/Dawson",
  "America/Dawson_Creek":"America/Dawson Creek",
  "America/Denver":"America/Denver",
  "America/Detroit":"America/Detroit",
  "America/Edmonton":"America/Edmonton",
  "America/Eirunepe":"America/Eirunepe",
  "America/El_Salvador":"America/El Salvador",
  "America/Fort_Nelson":"America/Fort Nelson",
  "America/Fortaleza":"America/Fortaleza",
  "America/Glace_Bay":"America/Glace Bay",
  "America/Godthab":"America/Godthab",
  "America/Goose_Bay":"America/Goose Bay",
  "America/Grand_Turk":"America/Grand Turk",
  "America/Guatemala":"America/Guatemala",
  "America/Guayaquil":"America/Guayaquil",
  "America/Guyana":"America/Guyana",
  "America/Halifax":"America/Halifax",
  "America/Havana":"America/Havana",
  "America/Hermosillo":"America/Hermosillo",
  "America/Indiana/Indianapolis":"America/Indiana/Indianapolis",
  "America/Indiana/Knox":"America/Indiana/Knox",
  "America/Indiana/Marengo":"America/Indiana/Marengo",
  "America/Indiana/Petersburg":"America/Indiana/Petersburg",
  "America/Indiana/Tell_City":"America/Indiana/Tell City",
  "America/Indiana/Vevay":"America/Indiana/Vevay",
  "America/Indiana/Vincennes":"America/Indiana/Vincennes",
  "America/Indiana/Winamac":"America/Indiana/Winamac",
  "America/Inuvik":"America/Inuvik",
  "America/Iqaluit":"America/Iqaluit",
  "America/Jamaica":"America/Jamaica",
  "America/Juneau":"America/Juneau",
  "America/Kentucky/Louisville":"America/Kentucky/Louisville",
  "America/Kentucky/Monticello":"America/Kentucky/Monticello",
  "America/La_Paz":"America/La Paz",
  "America/Lima":"America/Lima",
  "America/Los_Angeles":"America/Los Angeles",
  "America/Maceio":"America/Maceio",
  "America/Managua":"America/Managua",
  "America/Manaus":"America/Manaus",
  "America/Martinique":"America/Martinique",
  "America/Matamoros":"America/Matamoros",
  "America/Mazatlan":"America/Mazatlan",
  "America/Menominee":"America/Menominee",
  "America/Merida":"America/Merida",
  "America/Metlakatla":"America/Metlakatla",
  "America/Mexico_City":"America/Mexico City",
  "America/Miquelon":"America/Miquelon",
  "America/Moncton":"America/Moncton",
  "America/Monterrey":"America/Monterrey",
  "America/Montevideo":"America/Montevideo",
  "America/Nassau":"America/Nassau",
  "America/New_York":"America/New York",
  "America/Nipigon":"America/Nipigon",
  "America/Nome":"America/Nome",
  "America/Noronha":"America/Noronha",
  "America/North_Dakota/Beulah":"America/North Dakota/Beulah",
  "America/North_Dakota/Center":"America/North Dakota/Center",
  "America/North_Dakota/New_Salem":"America/North Dakota/New Salem",
  "America/Ojinaga":"America/Ojinaga",
  "America/Panama":"America/Panama",
  "America/Pangnirtung":"America/Pangnirtung",
  "America/Paramaribo":"America/Paramaribo",
  "America/Phoenix":"America/Phoenix",
  "America/Port-au-Prince":"America/Port-au-Prince",
  "America/Port_of_Spain":"America/Port of Spain",
  "America/Porto_Velho":"America/Porto Velho",
  "America/Puerto_Rico":"America/Puerto Rico",
  "America/Punta_Arenas":"America/Punta Arenas",
  "America/Rainy_River":"America/Rainy River",
  "America/Rankin_Inlet":"America/Rankin Inlet",
  "America/Recife":"America/Recife",
  "America/Regina":"America/Regina",
  "America/Resolute":"America/Resolute",
  "America/Rio_Branco":"America/Rio Branco",
  "America/Santarem":"America/Santarem",
  "America/Santiago":"America/Santiago",
  "America/Santo_Domingo":"America/Santo Domingo",
  "America/Sao_Paulo":"America/Sao Paulo",
  "America/Scoresbysund":"America/Scoresbysund",
  "America/Sitka":"America/Sitka",
  "America/St_Johns":"America/St Johns",
  "America/Swift_Current":"America/Swift Current",
  "America/Tegucigalpa":"America/Tegucigalpa",
  "America/Thule":"America/Thule",
  "America/Thunder_Bay":"America/Thunder Bay",
  "America/Tijuana":"America/Tijuana",
  "America/Toronto":"America/Toronto",
  "America/Vancouver":"America/Vancouver",
  "America/Whitehorse":"America/Whitehorse",
  "America/Winnipeg":"America/Winnipeg",
  "America/Yakutat":"America/Yakutat",
  "America/Yellowknife":"America/Yellowknife",
  "Antarctica/Casey":"Antarctica/Casey",
  "Antarctica/Davis":"Antarctica/Davis",
  "Antarctica/DumontDUrville":"Antarctica/DumontDUrville",
  "Antarctica/Macquarie":"Antarctica/Macquarie",
  "Antarctica/Mawson":"Antarctica/Mawson",
  "Antarctica/Palmer":"Antarctica/Palmer",
  "Antarctica/Rothera":"Antarctica/Rothera",
  "Antarctica/Syowa":"Antarctica/Syowa",
  "Antarctica/Troll":"Antarctica/Troll",
  "Antarctica/Vostok":"Antarctica/Vostok",
  "Asia/Almaty":"Asia/Almaty",
  "Asia/Amman":"Asia/Amman",
  "Asia/Anadyr":"Asia/Anadyr",
  "Asia/Aqtau":"Asia/Aqtau",
  "Asia/Aqtobe":"Asia/Aqtobe",
  "Asia/Ashgabat":"Asia/Ashgabat",
  "Asia/Atyrau":"Asia/Atyrau",
  "Asia/Baghdad":"Asia/Baghdad",
  "Asia/Baku":"Asia/Baku",
  "Asia/Bangkok":"Asia/Bangkok",
  "Asia/Barnaul":"Asia/Barnaul",
  "Asia/Beirut":"Asia/Beirut",
  "Asia/Bishkek":"Asia/Bishkek",
  "Asia/Brunei":"Asia/Brunei",
  "Asia/Chita":"Asia/Chita",
  "Asia/Choibalsan":"Asia/Choibalsan",
  "Asia/Colombo":"Asia/Colombo",
  "Asia/Damascus":"Asia/Damascus",
  "Asia/Dhaka":"Asia/Dhaka",
  "Asia/Dili":"Asia/Dili",
  "Asia/Dubai":"Asia/Dubai",
  "Asia/Dushanbe":"Asia/Dushanbe",
  "Asia/Famagusta":"Asia/Famagusta",
  "Asia/Gaza":"Asia/Gaza",
  "Asia/Hebron":"Asia/Hebron",
  "Asia/Ho_Chi_Minh":"Asia/Ho Chi Minh",
  "Asia/Hong_Kong":"Asia/Hong Kong",
  "Asia/Hovd":"Asia/Hovd",
  "Asia/Irkutsk":"Asia/Irkutsk",
  "Asia/Jakarta":"Asia/Jakarta",
  "Asia/Jayapura":"Asia/Jayapura",
  "Asia/Jerusalem":"Asia/Jerusalem",
  "Asia/Kabul":"Asia/Kabul",
  "Asia/Kamchatka":"Asia/Kamchatka",
  "Asia/Karachi":"Asia/Karachi",
  "Asia/Kathmandu":"Asia/Kathmandu",
  "Asia/Khandyga":"Asia/Khandyga",
  "Asia/Kolkata":"Asia/Kolkata",
  "Asia/Krasnoyarsk":"Asia/Krasnoyarsk",
  "Asia/Kuala_Lumpur":"Asia/Kuala Lumpur",
  "Asia/Kuching":"Asia/Kuching",
  "Asia/Macau":"Asia/Macau",
  "Asia/Magadan":"Asia/Magadan",
  "Asia/Makassar":"Asia/Makassar",
  "Asia/Manila":"Asia/Manila",
  "Asia/Nicosia":"Asia/Nicosia",
  "Asia/Novokuznetsk":"Asia/Novokuznetsk",
  "Asia/Novosibirsk":"Asia/Novosibirsk",
  "Asia/Omsk":"Asia/Omsk",
  "Asia/Oral":"Asia/Oral",
  "Asia/Pontianak":"Asia/Pontianak",
  "Asia/Pyongyang":"Asia/Pyongyang",
  "Asia/Qatar":"Asia/Qatar",
  "Asia/Qyzylorda":"Asia/Qyzylorda",
  "Asia/Riyadh":"Asia/Riyadh",
  "Asia/Sakhalin":"Asia/Sakhalin",
  "Asia/Samarkand":"Asia/Samarkand",
  "Asia/Seoul":"Asia/Seoul",
  "Asia/Shanghai":"Asia/Shanghai",
  "Asia/Singapore":"Asia/Singapore",
  "Asia/Srednekolymsk":"Asia/Srednekolymsk",
  "Asia/Taipei":"Asia/Taipei",
  "Asia/Tashkent":"Asia/Tashkent",
  "Asia/Tbilisi":"Asia/Tbilisi",
  "Asia/Tehran":"Asia/Tehran",
  "Asia/Thimphu":"Asia/Thimphu",
  "Asia/Tokyo":"Asia/Tokyo",
  "Asia/Tomsk":"Asia/Tomsk",
  "Asia/Ulaanbaatar":"Asia/Ulaanbaatar",
  "Asia/Urumqi":"Asia/Urumqi",
  "Asia/Ust-Nera":"Asia/Ust-Nera",
  "Asia/Vladivostok":"Asia/Vladivostok",
  "Asia/Yakutsk":"Asia/Yakutsk",
  "Asia/Yangon":"Asia/Yangon",
  "Asia/Yekaterinburg":"Asia/Yekaterinburg",
  "Asia/Yerevan":"Asia/Yerevan",
  "Atlantic/Azores":"Atlantic/Azores",
  "Atlantic/Bermuda":"Atlantic/Bermuda",
  "Atlantic/Canary":"Atlantic/Canary",
  "Atlantic/Cape_Verde":"Atlantic/Cape Verde",
  "Atlantic/Faroe":"Atlantic/Faroe",
  "Atlantic/Madeira":"Atlantic/Madeira",
  "Atlantic/Reykjavik":"Atlantic/Reykjavik",
  "Atlantic/South_Georgia":"Atlantic/South Georgia",
  "Atlantic/Stanley":"Atlantic/Stanley",
  "Australia/Adelaide":"Australia/Adelaide",
  "Australia/Brisbane":"Australia/Brisbane",
  "Australia/Broken_Hill":"Australia/Broken Hill",
  "Australia/Currie":"Australia/Currie",
  "Australia/Darwin":"Australia/Darwin",
  "Australia/Eucla":"Australia/Eucla",
  "Australia/Hobart":"Australia/Hobart",
  "Australia/Lindeman":"Australia/Lindeman",
  "Australia/Lord_Howe":"Australia/Lord Howe",
  "Australia/Melbourne":"Australia/Melbourne",
  "Australia/Perth":"Australia/Perth",
  "Australia/Sydney":"Australia/Sydney",
  "Europe/Amsterdam":"Europe/Amsterdam",
  "Europe/Andorra":"Europe/Andorra",
  "Europe/Astrakhan":"Europe/Astrakhan",
  "Europe/Athens":"Europe/Athens",
  "Europe/Belgrade":"Europe/Belgrade",
  "Europe/Berlin":"Europe/Berlin",
  "Europe/Brussels":"Europe/Brussels",
  "Europe/Bucharest":"Europe/Bucharest",
  "Europe/Budapest":"Europe/Budapest",
  "Europe/Chisinau":"Europe/Chisinau",
  "Europe/Copenhagen":"Europe/Copenhagen",
  "Europe/Dublin":"Europe/Dublin",
  "Europe/Gibraltar":"Europe/Gibraltar",
  "Europe/Helsinki":"Europe/Helsinki",
  "Europe/Istanbul":"Europe/Istanbul",
  "Europe/Kaliningrad":"Europe/Kaliningrad",
  "Europe/Kiev":"Europe/Kiev",
  "Europe/Kirov":"Europe/Kirov",
  "Europe/Lisbon":"Europe/Lisbon",
  "Europe/London":"Europe/London",
  "Europe/Luxembourg":"Europe/Luxembourg",
  "Europe/Madrid":"Europe/Madrid",
  "Europe/Malta":"Europe/Malta",
  "Europe/Minsk":"Europe/Minsk",
  "Europe/Monaco":"Europe/Monaco",
  "Europe/Moscow":"Europe/Moscow",
  "Europe/Oslo":"Europe/Oslo",
  "Europe/Paris":"Europe/Paris",
  "Europe/Prague":"Europe/Prague",
  "Europe/Riga":"Europe/Riga",
  "Europe/Rome":"Europe/Rome",
  "Europe/Samara":"Europe/Samara",
  "Europe/Saratov":"Europe/Saratov",
  "Europe/Simferopol":"Europe/Simferopol",
  "Europe/Sofia":"Europe/Sofia",
  "Europe/Stockholm":"Europe/Stockholm",
  "Europe/Tallinn":"Europe/Tallinn",
  "Europe/Tirane":"Europe/Tirane",
  "Europe/Ulyanovsk":"Europe/Ulyanovsk",
  "Europe/Uzhgorod":"Europe/Uzhgorod",
  "Europe/Vienna":"Europe/Vienna",
  "Europe/Vilnius":"Europe/Vilnius",
  "Europe/Volgograd":"Europe/Volgograd",
  "Europe/Warsaw":"Europe/Warsaw",
  "Europe/Zaporozhye":"Europe/Zaporozhye",
  "Europe/Zurich":"Europe/Zurich",
  "Indian/Chagos":"Indian/Chagos",
  "Indian/Christmas":"Indian/Christmas",
  "Indian/Cocos":"Indian/Cocos",
  "Indian/Kerguelen":"Indian/Kerguelen",
  "Indian/Mahe":"Indian/Mahe",
  "Indian/Maldives":"Indian/Maldives",
  "Indian/Mauritius":"Indian/Mauritius",
  "Indian/Reunion":"Indian/Reunion",
  "Pacific/Apia":"Pacific/Apia",
  "Pacific/Auckland":"Pacific/Auckland",
  "Pacific/Bougainville":"Pacific/Bougainville",
  "Pacific/Chatham":"Pacific/Chatham",
  "Pacific/Chuuk":"Pacific/Chuuk",
  "Pacific/Easter":"Pacific/Easter",
  "Pacific/Efate":"Pacific/Efate",
  "Pacific/Enderbury":"Pacific/Enderbury",
  "Pacific/Fakaofo":"Pacific/Fakaofo",
  "Pacific/Fiji":"Pacific/Fiji",
  "Pacific/Funafuti":"Pacific/Funafuti",
  "Pacific/Galapagos":"Pacific/Galapagos",
  "Pacific/Gambier":"Pacific/Gambier",
  "Pacific/Guadalcanal":"Pacific/Guadalcanal",
  "Pacific/Guam":"Pacific/Guam",
  "Pacific/Honolulu":"Pacific/Honolulu",
  "Pacific/Kiritimati":"Pacific/Kiritimati",
  "Pacific/Kosrae":"Pacific/Kosrae",
  "Pacific/Kwajalein":"Pacific/Kwajalein",
  "Pacific/Majuro":"Pacific/Majuro",
  "Pacific/Marquesas":"Pacific/Marquesas",
  "Pacific/Nauru":"Pacific/Nauru",
  "Pacific/Niue":"Pacific/Niue",
  "Pacific/Norfolk":"Pacific/Norfolk",
  "Pacific/Noumea":"Pacific/Noumea",
  "Pacific/Pago_Pago":"Pacific/Pago Pago",
  "Pacific/Palau":"Pacific/Palau",
  "Pacific/Pitcairn":"Pacific/Pitcairn",
  "Pacific/Pohnpei":"Pacific/Pohnpei",
  "Pacific/Port_Moresby":"Pacific/Port Moresby",
  "Pacific/Rarotonga":"Pacific/Rarotonga",
  "Pacific/Tahiti":"Pacific/Tahiti",
  "Pacific/Tarawa":"Pacific/Tarawa",
  "Pacific/Tongatapu":"Pacific/Tongatapu",
  "Pacific/Wake":"Pacific/Wake",
  "Pacific/Wallis":"Pacific/Wallis"
}