Ahead of today's opening session for the Malaysia Grand Prix, the air temperature is 29 degrees C while the track temperature is 34 degrees. Humidity is 71 percent.

With its long straights and flowing corners, this is a track that, in recent years, has traditionally suited Red Bull, however, so it will be interesting to see how things develop this year.

Following the disappointment of Melbourne, Mercedes insists it is working hard on its tyre problem, while Ferrari has its own issues to deal with.

Only one reserve driver is in action this morning, Valtteri Bottas replacing Bruno Senna in the second Williams.

Vergne heads the queue at the end of the pitlane, and when the lights go green Kovalainen, Perez, Karthikeyan, Ricciardo and Kobayashi are among the drivers following the Frenchman on his installation lap.

Tyre compounds are hard and medium, while, as previously reported, following his nightmare in Melbourne, Massa has been provided with a new chassis.

Within five minutes everyone has been out, Maldonado, Rosberg, Schumacher, di Resta and Bottas completing two laps.

Ten minutes into the session both Toro Rossos are on track, along with di Resta. While Ricciardo returns to the pits, Vergne and di Resta remain on track, joined by Glock. The Scot posts 2:04.524 while Vergne dives into the pitlane.

A 44.935 sees Glock go straight to the top of the timesheet, as Pic and Karthikeyan head down the pitlane.

Glock improves with a 43.487 as Button heads down the pitlane, the first of the big guns to come out for a second run. Unsurprisingly, the Englishman is quickest in the first sector, and again in the second. As de la Rosa posts 2:25.817, Button crosses the line at 39.323, almost 47s quicker.

The circuit, which gets very little use throughout the year, is very dusty, as proven by Perez who runs wide on his way to posting a 42.858.

Raikkonen goes quickest with a 39.128 as Massa and Schumacher get to work.

As Pirelli claims that there will be rain later in the afternoon, Massa goes third (39.904) ahead of Kobayashi and Perez. Elsewhere, Grosjean is going very slowly, the Frenchman concerned that there is something wrong at the back of his car.

Schumacher's first flying lap sees the German go quickest with a 39.083, as teammate Rosberg, Alonso and Webber leave the pits. Grosjean is back in the pits, his problem appearing to be a broken hub.

As Webber goes fourth (39.657), Hamilton begins his first flying lap, the Englishman immediately going quickest in the first sector. Rosberg posts 39.323 - exactly the same time as Button - to go fourth, but is demoted to fifth when Hamilton goes quickest with a 38.598. Sam Michael watches intently from the pitwall.

Vettel leaves the pits with 55:00 on the clock, still no time from Ricciardo, Pic, Grosjean, Maldonado, Alonso or Bottas.

A 38.535 sees Vettel go straight to the top of the timesheet, ahead of Hamilton, Schumacher, Rosberg, Raikkonen, Button, Webber, Massa, Kobayashi and Hulkenberg.

Rosberg is one of the few to improve his time, the German posting 38.813 to take third. That said, moments later Hamilton re-takes the top spot with a 38.021.

A massive slide, beautifully held, for di Resta as the Scot improves to twelfth with a 40.001.

More misery for HRT as Karthikeyan stops on the back straight, much as he did in FP1 last week. With the Indian seemingly suffering a hydraulics issue, de la Rosa also appears to have problems, the Spaniard having been pushed back into his garage.

Although the sun is shining, it is reported that there are "lots of rain showers appearing on the radar".

Di Resta improves to seventh (39.298), two spots ahead of his German teammate.

With his hub issue resolved, Grosjean is back on track and improving to fifth with a 38.919. Elsewhere, HRT appears to be trying everything it can as de la Rosa complains of no rear grip. The Spanish veteran giving detailed feedback to his engineers.