$TimeZone
gives the current time zone to assume for dates and times.
Details

- The time zone gives the number of hours that must be added to Greenwich Mean Time (GMT) to obtain local time.
- US Eastern Standard Time (EST) corresponds to time zone -5.
- Daylight saving time corrections must be included in the time zone, so US Eastern Daylight Time (EDT) corresponds to time zone -4.
- $TimeZone defaults to $SystemTimeZone.
- $TimeZone=z resets the current time zone for purposes of functions like DateString, DateList, and AbsoluteTime.
- Settings for $TimeZone may be an Integer, Real, or time zone String.
Examples
Wolfram Research (2007), $TimeZone, Wolfram Language function, https://reference.wolfram.com/language/ref/$TimeZone.html (updated 2014).
Text
Wolfram Research (2007), $TimeZone, Wolfram Language function, https://reference.wolfram.com/language/ref/$TimeZone.html (updated 2014).
BibTeX
BibLaTeX
CMS
Wolfram Language. 2007. "$TimeZone." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2014. https://reference.wolfram.com/language/ref/$TimeZone.html.
APA
Wolfram Language. (2007). $TimeZone. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/$TimeZone.html