You want to manually set the date and time on your Raspberry Pi.
Use the Linux date command.
The date and time format is MMDDHHMMYYYY, where MM is the month number, DD the day of the month, HH and MM the hours and minutes, respectively, and YYYY the year.
For example:
$ sudo date 010203042013 Wed Jan 2 03:04:00 UTC 2013 |
Discussion
If the Raspberry Pi is connected to the Internet, then as it boots up it will automatically set its own time using an Internet time server.
You can also use date to display the UTC time by just entering date on its own:
$ date Wed Jan 2 03:08:14 UTC 2013 |
See Also
If you want your Raspberry Pi to maintain the correct time, even when there is no network, then you can use an RTC (real-time clock) module (Recipe 11.13).