How to create custome Time Zone in AIX

For example:
I want to create a custom me zone, which will use the same days as the standard EU switch to and from Summertime only the time has been altered. Summertime begins at 07:30 on the last Sunday of March and ends at 08:30 on the last Sunday of October. And making two states like MCST (My Company Standard Time) and MCDT (My Company Daylight Time).

Solution:

set the occurrence of the Sunday as last occurrence in that month (As you needed), a value of 5 indicates the last day (0=sunday) in month and which may occur either in 4th or 5th week (sometimes 5 Sundays in a month), edit your /etc/environment and set the TZ as below,

TZ=Your time zone,M3.5.0/7:30:00,M10.5.0/8:30:00
Ensure that the time zone value ends with DT for the DST to be enabled.