Rain could make this weekend's Malaysian grand prix both "interesting" and "distressing", according to McLaren managing director Jonathan Neale.
At present, there is a high chance of rain - as well as the usual hot and humid conditions - for the Sepang event.
This time, a new factor is the Pirelli tyres, with the Italian supplier's wet-weather products yet to be fully tested and understood.
A high possibility of rain will make it very interesting for all of the spectators
"A high possibility of rain will make it very interesting for all of the spectators and very distressing for all of us teams," Neale said during a media teleconference.
To EFE news agency, reserve driver Pedro de la Rosa said: "The Malaysia conditions are extreme on all levels, especially the temperature and humidity but also the amount of water on the track in the case of rain."