Time(zone)s relative to UTC

Current UTC date and time: Sat Apr 21 11:35:44 UTC 2018

Daylight Time:
ADT (Atlantic Daylight Time): subtract 3 hours from UTC -->
EDT (Eastern Daylight Time):  subtract 4 hours from UTC -->
CDT (Central Daylight Time):  subtract 5 hours from UTC -->
MDT (Mountain Daylight Time): subtract 6 hours from UTC -->
PDT (Pacific Daylight Time):  subtract 7 hours from UTC -->
 
Standard Time:
AST (Atlantic Standard Time): subtract 4 hours from UTC -->
EST (Eastern Standard Time):  subtract 5 hours from UTC -->
CST (Central Standard Time):  subtract 6 hours from UTC -->
MST (Mountain Standard Time): subtract 7 hours from UTC -->
PST (Pacific Standard Time):  subtract 8 hours from UTC -->

Most Caribbean Islands observe AST (no daylight saving
time), for a list see: sizes.com.

UTC = Coordinated Universal Time; same as Greenwich
Mean Time (GMT), Zulu Time (Z).