Ahead of today second free practice session, the air temperature is 20 degrees and the track temperature is 22 degrees. The rain stopped some time ago and the track is now fairly dry, though there is talk of rain later in the session.

The weather conditions earlier meant that no serious conclusions could be drawn, other than for the fact that Lewis Hamilton has already compromised his weekend after crashing heavily and badly damaging the rear end of his MP4-25.

When the lights go green Kobayashi and Trulli lead the way, quickly followed by di Grassi. The Japanese driver soon finds the two parts of track that remain wet, while his crew advises that no rain is expected for the next half hour at least.

Despite a couple of nasty 'tank slappers', Kobayashi posts a 1:32.205, while Vettel waits patiently in the Red Bull garage as his mechanics change his engine.

Overhead shot show that in some corners the dry line fades away, however, this doesn't stop de la Rosa posting a 25.160. Next time around the Spanish veteran raises the benchmark with a 23.512.

Webber's first flying lap sees the Australian go third with a 24.659, however, he is soon demoted by Kobayashi (23.402). Sutil (currently second) has a big moment at the hairpin.

For a brief moment Liuzzi (20.866) makes it a Force India 1-2, however, de la rosa re-takes the top spot with a 20.164.

As Webber has a big moment, Alonso goes quickest in the first sector. Having gone quickest in the second sector the two-time world champion goes quickest with an 18.307. Teammate Massa is fifth (19.835) just ahead of Button.

While Schumacher and Vettel have yet to post times, Hamilton has yet to make an appearance.

Massa makes it a Ferrari 1-2 with an 18.760, as Schumacher goes eleventh with a 20.131 before improving with an 18.791 to go third.

Rosberg heads back to the pits with his front wing seriously awry, the replay shows he clouted a bollard at Turn 1.

Twenty five minutes into the session, Alguersuari and Webber are the first drivers to switch to the option (super-soft) tyres, at which point it begins to rain. Webber has a slight wobble as Alguersuari improves to 20.310. The Australian posts a personal best in the second sector but fails to improve overall as the radar reveals a massive rain cloud heading towards the circuit.

Despite being shown the slippery track surface flag, Kovalainen gets it all wrong as the rain begins to fall just that tiny bit harder. Suddenly, nobody is improving, times being around half-a-second or so off what they were.

Vettel goes off at Turn 12 but somehow misses the tyre barrier and makes it through the gravel. A great escape for the German.

The shower having ceased, Hulkenberg goes quickest in the second sector, improving to second overall with a 18.546. Moments later, Webber goes quickest in the second sector, the Australian running on the option tyre. Having gone quickest in the final sector also, the Red Bull driver goes quickest with a 17.840.

There's a misunderstanding between Schumacher and di Grassi which sees the German run wide, having hit a wet patch. Elsewhere, Webber improves with a 17.409.

With the track now dry again the times are tumbling, with Alonso going quickest (17.329) and Rosberg and Schumacher making it a Mercedes 3-4.

A 17.011 sees Massa go quickest, but Webber soon re-takes the top spot with a 16.585.

Behind Webber, Alonso and Massa, Barrichello improves to fourth with a 17.160. Moments later, as something falls from one of the Renaults, Alonso posts 16.265 to go quickest.

On options, Schumacher posts personal bests in all three sectors and consequently goes fourth with a 16.971. Elsewhere, Vettel is now back on track and on options. He goes quickest overall in the second sector, crossing the line at 16.609 to go third. Two laps later the Red Bull driver goes second with a 16.294 but it remains to be seen whether the options will be good enough for another lap and another improvement.

Webber and Liuzzi both have moments, indeed, a number of drivers still struggling to stay on the black stuff.