strtotime php-current time zone

strtotime()parsing is always done with the current time zone,
unless a different time zone is specified in the string that is parsed:
echo date("H:i T\n", strtotime("09:22")); // shows 09:22 CET
echo date("H:i T\n\n", strtotime("09:22 GMT")); // shows 10:22 CET
echo gmdate("H:i T\n", strtotime("09:22")); // shows 08:22 GMT
echo gmdate("H:i T\n", strtotime("09:22 GMT")); // shows 09:22 GMT

Using the strtotime()function is easy. It accepts two parameters: the
string to parse to a timestamp and an optional timestamp. If the
 timestamp is included, the time is converted relative to the
 timestamp; if it’s not included,the current time is used. The relative
 calculations are only written with yesterday, tomorrow, and the 1
 year 2 days ago format strings.