On Fri, Sep 25, 2015 at 10:28 PM, Tim Peters <tim.peters@gmail.com> wrote:

So it seems a sufficient condition is that there's at most one UTC offset change in the last 24 hours.

Apparently [1] we are not alone in wanting this condition. [1]: http://mm.icann.org/pipermail/tz/2015-June/022309.html