Hi,
My 2014 4/4 usually warms up to spot on 90 and then sticks there.
When warmed up the oil pressure registers at 4 when on the move.
But, unlike you, I have been a bit wimpish of late and been driving with hood up

- my excuse is that on dirty roads I find spray blows in and covers the interior in a layer of mucky water.

So the temperature difference could be explained by you having the hood down and heater full on.
Adrian