Time(zone)s relative to UTC

Current UTC date and time: Fri Dec 15 12:02:12 UTC 2017

Daylight Time:
ADT (Atlantic Daylight Time): subtract 3 hours from UTC --> 09:02
EDT (Eastern Daylight Time):  subtract 4 hours from UTC --> 08:02
CDT (Central Daylight Time):  subtract 5 hours from UTC --> 07:02
MDT (Mountain Daylight Time): subtract 6 hours from UTC --> 06:02
PDT (Pacific Daylight Time):  subtract 7 hours from UTC --> 05:02
 
Standard Time:
AST (Atlantic Standard Time): subtract 4 hours from UTC --> 08:02
EST (Eastern Standard Time):  subtract 5 hours from UTC --> 07:02
CST (Central Standard Time):  subtract 6 hours from UTC --> 06:02
MST (Mountain Standard Time): subtract 7 hours from UTC --> 05:02
PST (Pacific Standard Time):  subtract 8 hours from UTC --> 04:02

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).