It was very hot this summer in Vegas area.
We saw over 50C (120F+) frequently during our test trip. (not BMW)
If you want to see any test vehicle, go here during summer time.
https://goo.gl/maps/hM64ywcqWzm
This is very typical hot temperature hill climb test spot.
It's about 1.5 hr from Vegas. (called Davis dam hill)