I was down there this morning around 11am cloudless sky with the sun beating down and too a couple of colour pictures (film) that I am going to process this evening now it is cooler.
When I got back to the multi-storey car park, the onboard thermometer told me it was (only) 27C but as soon as I drove out it missed the intermediate numbers and stuck at 35C and only when I got home (800 feet up) it was a more reasonable 29c.
The amount of green algae growing on the surface of the River Wear came as a surprise seeing that there was still quite a steady flow downstream.