Mark Webber thinks the lower than expected temperatures in Austin could be the biggest hindrance for Red Bull at this weekend's United States Grand Prix.
Following a recent warm spell in the city, the temperatures have reverted to their more usual autumnal lows this week - and it is much cooler than Formula 1 teams have experienced at recent venues.
With tyre temperatures having been such an important factor in the battle for victories this season, the cooler conditions could deliver a decisive swing in the tight battle at the front of the field.
Red Bull's car is believed to operate at a warmer tyre operating window than title rival Ferrari, so cooler conditions will hurt it more.
The temperature problem is also exacerbated by the fact that Pirelli has opted to bring the medium and hard tyres to the United States - which operate in a much warmer window compared to the super softs and softs.
Webber thinks that although the fast swoops of the Austin track appear to be the ideal stomping ground for Red Bull's car, if the team cannot get its tyres working then track characteristics will not be a help at all.
"I think the form card recently, apart from Abu Dhabi, has been very strong," he said. "Qualifying was strong in Abu Dhabi, at Suzuka we had the front row and cleaned up, and the other two races [Korea and India] were very strong [for Red Bull].
"If we get back to that sort of form and you are in the hunt then victories are there.
"But temperature is very important. Layout is not very important, temperatures are. If the black things on the corners are not working then you can put the layout up your arse - it is not going to work.
"You need to have everything working together. I think the layout will not be too bad for us, but temperatures and understanding the tyres will be important."
Although Red Bull's RB8 has been the standout car since the Singapore GP, Webber thinks there is still room to improve it.
"People talk about it being the best car... it is fast but there are still areas we need to work on, which we don't make for general consumption," he said.
"We have to work on those as a team and I think it has been a credit to the team how much we have developed the car through the year."