Ahead of today's second practice session, the air temperature is 21 degrees C, while the track temperature is 24 degrees. The rain clouds are still hovering and it remains humid.

Hamilton led the way this morning, ahead of the usual suspects, while Webber lost track time after running wide and hitting the barriers when he lost grip on the damp Astroturf.

Alguersuari heads the traffic jam at the end of the pitlane and as the lights go green the Spaniard is followed by Ricciardo, d'Ambrosio and Glock.

The Toro Rosso driver posts 27.596, however, attention shifts to teammate Buemi who is on the supersoft (option) tyre, the Swiss no doubt hoping to get in a few exploratory laps before the rain clouds open up.

Just four minutes into the session there are eleven names on the timesheets, Perez (25.881) leading the way, ahead of Heidfeld and Alguersuari.

With twenty-two drivers on track traffic is already a problem, however, that doesn't stop Petrov raising the bar with a 25.124.

On his first flying lap, Massa goes quickest (22.928) as Hamilton goes second with a 23.593. Elsewhere, countryman Barrichello complains of understeer. The Williams driver overtakes d'Ambrosio as they enter the pitlane, causing the Belgian to have to move off line.

Business as usual as Vettel, on his first flying lap, goes quickest with a 22.66, the German going quickest in the final two sectors.

No sooner has Alonso gone quickest (22.297) than Button pops up in second (22.539), however, moments later Vettel splits the pair with a 22.392. Massa, having gone quickest in S1, locks up going into Turn 12 and spins the Ferrari.

As the drivers head up to Turn 11, the dark clouds in the distance are highly noticeable.

Button goes quickest with a 22.091 as a mistake in the final sector sees Vettel run wide and thereby fail to improve.

Alguersuari, now on option tyres, goes seventh with a 24.182, as Alonso consolidates second with a 22.292. The TV camera cuts to Alguersuari's parents in the Toro Rosso motorhome… they look a little embarrassed.

Alonso improves with a 22.070 to go quickest, the top six places filled by the usual suspects.

Half an hour into the session the sun is finally beginning to break through. Drivers are now focussing on longer runs, some on primes, some on options.

With 52:00 on the clock, Massa is the first of the big guns to make the switch to options. The Brazilian immediately goes quickest but then runs wide in Turn 9 and aborts the lap. Elsewhere, Maldonado has a "small puncture on his left rear".

Next time around, Massa goes quickest in S2 as Alonso, also on options goes quickest in S1. Encountering traffic, the Brazilian fails to improve however, his Spanish teammate ups the ante with a 21.259.

The options appears to be good for a second a lap, at least, however, in Alonso's case at least, they don't appear good for two laps. We'll have to wait and see what Vettel and Webber get out of them.

Perez (options) goes seventh with a 23.399, like Alguersuari earlier unable to break in to the top six.

At half time, it's: Alonso, Button, Massa, Vettel, Hamilton, Webber, Perez, Alguersuari, di Resta and Sutil.

Ricciardo, on his first run on options, improves to twentieth with a 27.918, almost 7s off Alonso's pace. Elsewhere, Button (options) goes quickest in S1. Having posted a PB in S2 the McLaren driver posts 21.322 however, moments later teammate Hamilton takes the top spot with a 21.018.

Webber posts PBs in all three sectors as he improves to fourth with a 21.508, still the drivers fail to improve on their second flying lap.

As Maldonado improves to eighth, the Venezuelan having his first run on the options, we still await Vettel to appear on the supersoft rubber.

Rosberg's 22.121 sees the German break into the top six thereby demoting Vettel however, the world champion is on track on options.