(PHP 5 >= 5.1.0)
date_default_timezone_get — Gets the default timezone used by all date/time functions in a script
In order of preference, this function returns the default timezone by:
Reading the timezone set using the date_default_timezone_set() function (if any)
Reading the TZ environment variable (if non empty)
Reading the value of the date.timezone ini option (if set)
Querying the host operating system (if supported and allowed by the OS)
If none of the above succeed, date_default_timezone_get will return a default timezone of UTC.
Returns a string.