Cuba is located in Time Zone 19, whose midday is 75º West, crossing Yateras in the Province of Gauntánamo.
It is important to mention that, from the last Sunday of March to the last Sunday of October, summer time is established in Cuba acquiring the time of midday 60º West, and time is advanced one our so the difference between the Island's time and Greenwich's (GMT) is of one hour less.
Here are the hour differences between Cuba and some other countries: