Time(zone)s relative to UTC

Current UTC date and time: Sun Apr 21 23:00:43 UTC 2019

Daylight Saving Time:
     ADT (Atlantic Daylight Time): subtract 3 hours from UTC --> 20:00
     EDT (Eastern Daylight Time):  subtract 4 hours from UTC --> 19:00
     CDT (Central Daylight Time):  subtract 5 hours from UTC --> 18:00
     MDT (Mountain Daylight Time): subtract 6 hours from UTC --> 17:00
     PDT (Pacific Daylight Time):  subtract 7 hours from UTC --> 16:00
 
Standard Time:
     AST (Atlantic Standard Time): subtract 4 hours from UTC --> 19:00
     EST (Eastern Standard Time):  subtract 5 hours from UTC --> 18:00
     CST (Central Standard Time):  subtract 6 hours from UTC --> 17:00
     MST (Mountain Standard Time): subtract 7 hours from UTC --> 16:00
     PST (Pacific Standard Time):  subtract 8 hours from UTC --> 15:00

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).