Greenwich Mean Time (GMT) Formats

There are currently three formats for expressing date/time in Greenwich Mean Time (GMT). All examples represent the date, July 04, 2050. The time for all three formats is expressed as hour:minutes:seconds.

Standard Format

Here is the preferred, standard format¹ for the Internet. This format is defined by RFC 1123 (updated from RFC 822):

# RFC 1123 Standard GMT Format
Mon, 04 Jul 2050 07:07:07 GMT

The programming language C uses the ANSI standard format¹ in its asctime():

# ANSI Standard GMT Format
Mon Jul 4 07:07:07 2050

The RFC 850 format² is now obsolete (RFC 1036) and should not be used:

# RFC 850 Standard GMT Format [obsolete]
Monday, 04-Jul-50 07:07:07 GMT

Abbreviations

• ¹ Weekday : Mon, Tue, Wed, Thu, Fri, Sat, Sun
• ¹ Month: Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec
• ² Weekday: Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday
• ² Month: January, February, March, April, May, June, July, August, September, October, November, December

References

• Greenwich Mean Time Website
• Official US Time
• Time Zones

About the Author

Jeff Starr = Fullstack Developer. Book Author. Teacher. Human Being.