uphill down wind? or upwind downslope?

Of course the only answer is; 'It depends'. It depends on the relative wind
strength versus incline but It was something I became aware of on my latest
loop. the outbound leg was mostly upslope with the obvious local declines in
which I had the wind mostly at my back. It wasn't a strong wind, nor was the
overall elevation gain that serious even for Southern Ontario.
but when I did make my turn that less than noticeable semi-tailwind became
an annoying headwind when I was getting tired.

But it caused be to ponder the trade off between slope and wind.