Atlantic Standard Time Zone
Other parts of the world that keep time by subtracting four hours from UTC include: many Caribbean islands, including Puerto Rico, the U.S. Virgin Islands, and several South American countries, such as Paraguay, Chile, Bolivia, and parts of Brazil. Venezuela used AST until December 9, 2007, when it switched to UTC-4:30, but switched back to AST on May 1, 2016, at 2:30 a.m. local time.