Ahead of today's free practice session the air temperature is 28 degrees C, while the track temperature is 37 degrees.

Yesterday's opening session was held in ideal conditions, warm and bright, however, the last thirty minutes of the afternoon session was affected by a rain shower that turned out to be a little bit heavier than expected, leaving standing water and rivers on some parts of the track whilst others soon became dry.

There is talk of further rain this weekend, particularly on Sunday afternoon.

Lewis Hamilton was quickest in both session, with teammate Jenson Button and world championship leader Fernando Alonso in close attendance, however, it was the pace of the Red Bulls - or lack of it that was the main talking point.

While the Austrian team and Renault is playing down the significance of the FIA's ruling on engine mapping, claiming that it hasn't affected performance, others are not so sure. The times, coupled with the looks on the faces of Sebastian Vettel and Mark Webber appeared to reflect this.

Kovalainen is first out when the pitlane opens, the Finn followed by Grosjean and Petrov.

Within the first couple of minutes all but Vettel, Schumacher, Hulkenberg and Ricciardo have been out, most returning to their garages after the obligatory installation lap. Maldonado, Rosberg, Massa, Button and a couple of others stay out for a second lap.

Rosberg posts the first time of the day, the Mercedes driver crossing the line at 31.902, around 10s off yesterday's best from Hamilton. Moments later, Vergne posts 25.368.

Vettel's first flying lap, the German and his teammate getting to work surprisingly early, sees the world champion go quickest (24.537), however, he is soon demoted by Vergne and then Webber (23.359).

Not having run on the softer rubber yesterday, Marussia give their drivers a couple of laps before switching them back to mediums.

A 23.058 sees Vettel go quickest, 0.101s ahead of his teammate, with Hulkenberg third ahead of Vergne and Grosjean. However, we've yet to see the Ferraris or McLarens.

Raikkonen, who says he is now almost completely happy with the Lotus, posts 22.718, many believing the Finn to be this weekend's dark horse.

Drivers continue to run wide at certain corners. Notoriously dusty at the best of times, the rubber laid down yesterday morning was subsequently washed away by the rain shower. Grosjean runs wide at T4, Vettel also, while Webber does it at T6.

Senna pops up in third with a 23.052, as, with 40:51 on the clock, we have yet to see di Resta or the Ferraris post a time. Hamilton is eighth and Button eighteenth.

Hamilton goes quickest in S1 going on to post a PB in S2. At the line the McLaren driver posts 22.773 to go second, 0.055s off Raikkonen's time. Teammate Capt Grippy complains of "too much front end".

As the Ferrari duo finally climb into their cars, Alonso, in particular, looking very, very confident, Hamilton bangs in a 22.224 having gone quickest in the final two sectors.

Grosjean goes third with a 22.882 to make it a Lotus 2-3 as Vettel leaves the pits on softs, along with Vergne one of the first drivers to make the switch.

On the softer rubber, Vergne goes third (22.492) as Alonso heads down the pitlane.

Hamilton goes quickest in all three sectors, crossing the line at 21.706, the quickest lap of the weekend so far.

As Massa heads down the pitlane, Vettel goes quickest in S1, going on to post a PB in S2. At the line the German posts 21.671, just 0.035s quicker than Hamilton who was on mediums.

Webber (softs), goes quickest in S2, breaking the timing beam at 21.871 to go third. The early switch to softs combined with pace appears to suggest that Red Bull really is hurting no matter how much they deny it.

At half-time, it's: Vettel, Hamilton, Webber, Raikkonen, Vergne, Perez, Ricciardo, Grosjean, Senna and Maldonado.

Alonso's first lap sees the Spaniard go eighth (22.754) while Massa goes twenty-third (27.758). Elsewhere, Webber goes quickest with a 21.550.