User::getTimeZoneOffset

static function getTimeZoneOffset($userId = 0, $utc = false)
{
	$userId = intval($userId);
	// DO NOT set $userId = static::getId() when $userId == 0 here, because some times
	// CTimeZone::getOffset() returns different result when the first argument is null

	$disabled = !CTimeZone::enabled();

	if($disabled)
	{
		CTimeZone::enable();
	}

	$offset = static::getOffset($userId ? $userId : null) + ($utc ? BitrixTasksUtil::getServerTimeZoneOffset() : 0);

	if($disabled)
	{
		CTimeZone::disable();
	}

	return intval($offset);
}