After monsoonal rain halted running during last year’s twilight Malaysian grand prix, afternoon thunderstorms are again forecast for the 2010 edition at Sepang.
The race time has at least been brought forward from 5pm to 4pm for this weekend’s race outside Kuala Lumpur, after the grand prix last year ended in near-darkness.
But the threat of late afternoon rain, in unbearable humidity and high temperatures, has again been a feature in and around the city so far this week.
Mercedes’ Norbert Haug said: "This climate is the greatest challenge for the teams, cars and drivers."
The same sort of weather is forecast throughout the weekend, although the chance of very heavy rain is mercifully smaller for the decisive qualifying and race sessions on Saturday and Sunday.