15.9.1.9 Local time

Conversion from UTC to local time:

LocalTime = function(t){
return t + LocalTZA + DaylightSavingTA(t);
}

From local time to UTC:

UTC = function(t){
return t - LocalTZA - DaylightSavingTA(t - LocalTZA);
}

Note that UTC(LocalTime(t)) is not always equal to t.