The Atlantic Standard Time Zone (AST) is a geographic region that keeps time by subtracting four hours from Coordinated Universal Time (UTC).
In Canada, the provinces of New Brunswick, Prince Edward Island, and Nova Scotia are part of the Atlantic Standard Time Zone.
Other parts of the world that keep time by subtracting four hours from UTC include Bermuda, Puerto Rico, the US Virgin Islands, and many other Caribbean islands, as well as Venezuela, parts of Brazil and Argentina.
AST is known as Atlantic Daylight Time (ADT) during daylight saving time, and has one hour added to make it three hours behind UTC (UTC -3).