50°C on sunny days in summer before we added tile vents (it's a 100yr old roof, re-roofed in 1989 with dark tiles, and no economic way to put a vented ridge on it).
Thankfully it's nearly always windy here, and from memory the vents knocked at least 10-15C off that figure last summer.
You will have loads of insulation in your roof, but it's the decrement delay that also matters. How long does it take the heat to enter - and leave - the insulation?
You mount a chunk of crumbling sole plate on a plinth and give it to them as a Christmas present.
Many broken nights recently @Iceverge?