The IANA time zone identifiers for Greenwich Mean Time are GMT, Africa/Abidjan, Africa/Accra, Africa/Bamako, Africa/Banjul, Africa/Bissau, Africa/Conakry, Africa/Dakar, Africa/Freetown, Africa/Lome, Africa/Monrovia, Africa/Nouakchott, Africa/Ouagadougou, Africa/Sao_Tome, America/Danmarkshavn, Atlantic/Reykjavik と Atlantic/St_Helena.