Puddles of perspiration gave way to rivers of rain water yesterday as Southeast Asia's muggy humidity offered a harbinger of what lies ahead at this weekend's grand prix.
At precisely 4 o'clock, and as efficient as the Tag Heuer watch wrapped around Jenson Button's wrist, Malaysia's suffocating heat was supplanted by a downpour, followed by thunder.
"This is a fun place to race," said Button, the McLaren-Mercedes driver, ahead of today's first practice session at the Penang circuit, south of the capital. "The weather can really play a big part here, especially with the race starting at 4 o'clock. It is pretty much on the dot when it starts raining. It makes it really tricky for every team in the pit-lane and every driver to really understand the conditions and to make the right call."
Such was the immediacy of the 4pm change of weather yesterday that Renault's Vitaly Petrov had hardly finished towelling his sweaty brow when he found himself being ushered under an umbrella. Ferrari's Fernando Alonso, still dressed in his smart shorts, was forced to run through the sodden paddock to his scheduled conference.
"Anything can happen here, in terms of weather conditions," Alonso said. "The rain will make it a more stressful weekend. You need to be ready for all eventualities, and it would be useful if the opportunity arose [in practice] to try the extreme and intermediate rain tyres."
Petrov, the Russian driver who frustrated Alonso at the season-opening race in Australia two weeks ago by holding the Spaniard off to secure his first podium finish, expressed a higher degree of concern for Sunday's weather.
"When it rains here, it really rains," he said. "I am worried about high rains because of what happened in 2009."
Two seasons ago, Button claimed the top rung of the podium after only 31 laps of a 56-lap race when torrential rain forced the contest to be stopped. Sebastian Vettel, Red Bull Racing's world champion, warned that a similar scenario could unfold this weekend.
"It can become a bit chaotic," he said. "It seems to rain every day here, so the big questions are really when and how much? When it rains heavily, can we handle it, or will we not be able to control the cars?
"It will be a tricky one."
McLaren's Lewis Hamilton finished second in Australia, but he was a massive 22 seconds behind Vettel. His teammate, Button, said he is confident the Woking-based constructors have closed the gap on their rivals.
"We have more upgrades here, which will give us more lap time and better consistency," Button said. "We'll see a different race mostly because of the tyres in hot temperatures.
"We were surprised by how consistent the Pirellis were in the first race, but Sepang is a lot more demanding and tough on the four things that are touching the road."
Ferrari, who along with McLaren and Red Bull were seen as strong title contenders before last month's race in Melbourne, are hoping to bounce back this weekend. Alonso said that his performance at Albert Park was not as catastrophic as critics have portrayed it, but also warned that the true performance of the Italian manufacturers may not become apparent until after the Turkish Grand Prix on May 8.
"Everyone is saying it was a disaster, but I disagree," the Spaniard said. "We came fourth and finished ahead of [Mark] Webber and Button, who had led [us] after qualifying.
"It's true we need to improve the car, but we should also see how the next two or three races go, to see if the situation we experienced in Melbourne was the real thing.
"We believe we can be much more competitive and we will start by trying to have a better weekend here in Malaysia."