I've realized for a long time that temp. changes (80-90 deg. vs. 20-30 deg.) will almost always cause POI change with most powders. This is a huge reason to re-check a super load that you worked up in August if you plan on using it in Nov./Dec., or vice/versa. Some seem to be more prone to this than others, but I still feel they all show some susceptibility.
What I never paid attention to, however, was the humidity factor. I guess that's something I'll watch and record from now on. Been doing this stuff for a long, long time and never took that into consideration. Must have something to do with the air density factor, such as re-zeroing for a high-altitude hunt.