On Fri, 16 Mar 2018 18:04:04 +0000, Terry Pinnell wrote:

Is it possible that applications can somehow fail to use the PC's time
zone correctly? Or for that to be over-ruled by a BIOS facility?

My time zone is (UTC+OO:00) Dublin, Edinburgh, Lisbon, London. And I
have never changed it. But I'm baffled by an obscure problem with my
mapping program, Memory-Map, which I'd regarded as a bug. In short, when
I open any GPX file of a GPS recording made in the summer, two problems
arise:

1. It displays the time one hour earlier than the correct time. IOW it
displays the first trackpoint of a July walk that started at 09:00 as
08:00.


Seems it assumes DST was in effect at that time.