I was about to make a similar recommendation, but I think the one I am after is the one for determining seasons, which I think is a different App.
One reason I would suggest this kind of approach (identifying the periods of the year yourself rather than the time zone) is that it would give you more control, rather than what can be controlled by authorities choosing when the DST changeover may occur. I expect you could control this through definitions inside an RM rule as well, still without needing to use the time zone.
