As Europe bakes under yet another heatwave, memories from Austria are worrying Mercedes ahead of the German Grand Prix.

Temperatures are set to exceed 40 degrees in some parts of the continent, while at Hockenheim the thermometer will be in the mid-to-high 30s on Friday and Saturday.

That means the cooling issues which saw Mercedes' pace drop so sharply in the race at Spielberg may well return and team boss Toto Wolff is on alert.

“While there is much happening off track, our primary focus remains our on-track performance,” he said, as the team celebrates their 200th GP and 125 years of motorsport with a special livery.

“The weather forecast predicts high temperatures, which were extremely challenging for us in Austria, so we must stay vigilant.

“Like Spielberg, Hockenheim is also a relatively short circuit, which will close the gaps between different teams. We will stay humble and work hard to achieve the best possible result.”

Perhaps easing Mercedes' concerns is that Sunday is now set to be a lot cooler with temperatures of 26 degrees now expected and a threat of thunderstorms can't be ruled out either.