Calculating Daylight Saving Time

[gadelhas]

Unless you have a calendar you’d still want the data table anyway.
Any time you want to add or subtract time you need a calendar.

If the clock retrieves UTC time as 00:01 1st Jan 2016, and has to subtract one hour.
It has to know right down to days in month, leap years, the whole lot.

It's for this reason that is better work with epochtime.