I have some code like this:

public override void OnData(Slice data) { // called every minute

if (data.Time.Hour == 9 && data.Time.Minute <= 31) { // called every morning when the stock market opens
// initialize/rest something ...

I assume the stock market session starts at 9:30pm, so I do some routine each day first. However, do I need to do anything for Daylight Saving? In my backtesting, it seems alright, but I wonder why.

P.S. I know I can use schedule function to achieve this but still I may need to manipulate data hour/minute like above  sometimes.