Ahead of today's sole free practice session, the air temperature is 19 degrees C, while the track temperature is 22 degrees. There has been rain earlier this morning, indeed, for much of the night, and while it is not raining at this very moment the track is still damp and more of the wet stuff is expected within the hour.

After yesterday, it is still difficult to draw any serious conclusions, and that may well be the case as we head into qualifying and maybe even the race.

The Red Bulls look good - as expected - but so too do the Ferraris, while McLaren wasn't helped by Lewis Hamilton's crash in the opening session. Nonetheless, the Woking team insists that despite not having carried out as much testing as it would have wished it will persevere with the new aero package - including the blown diffuser - for the rest of the weekend.

Mercedes looked a lot better yesterday, while Renault, Williams and Force India also had their moments, as did Sauber which is celebrating 40 years in motorsport this weekend.

As the lights go green the first few drops begin to fall and around the tracks umbrellas are raised and pac-a-macs donned

Sakon Yamamoto - replacing Karun Chandhok this weekend - is told that while there will be rain for the first ten to fifteen minutes there will be no further rain during the session.

Jarno Trulli is first out, followed by Liuzzi, Glock, Yamamoto, Sutil, Alguersuari and Button, all appear to be on inters.

Sutil runs wide at Turn 11, some parts of the track damper than others as the rain continues to fall but only on some sections of the track. The worst possible scenario.

Five minutes into the session all but Barrichello have made an appearance. At which point the Brazilian veteran exits the Williams garage.

Local heroes, Rosberg and Schumacher come out for a second run, both on full wets.

Thirteen minutes into the session, after several minutes of total inactivity, Alguersuari, di Grassi and Vettel leave the pits. The rain appears to have stopped however, the hairpin remains very wet.

The Brazilian posts the first time of the day (1:37.406) however, moments later Vettel posts 29.911. More and more drivers pour on to the track.

Next time around di Grassi improves with a 33.800 while Vettel crosses the line at 28.330.

Replay show Rosberg getting it wrong at the hairpin. It is noticeable how dark the sky is.

As Vettel posts 27.311, Sutil slows with what appears to be a terminal problem. The German confirms it, telling his crew; "I've got a problem, I'm trying to get back to the pits but I've lost drive".

Hulkenberg goes second (29.465), ahead of Barrichello, Glock, di Grassi and Alonso.

As Vettel posts 24.988, Alonso posts personal bests in all three sectors to go fifth (33.144). The Spaniard making his way carefully past Sutil's struggling Force India.

As de la Rosa and Kobayashi make it a Sauber 2-3, Sutil finally arrives back at his garage. Well done that man!

Rosberg passes Schumacher when the seven-time champion runs wide at the hairpin. Still only ten names on the timesheets.

Schumacher goes quickest in S1 but this is instantly beaten by Kobayashi. The German posts a personal best in S2 finally crossing the line at 26.183 to go fifth.

A 24.542 sees Massa go quickest, however, the Brazilian is subsequently told to ease off as he is only meant to be scrubbing his tyres.

Kubica goes third (25.391) as Liuzzi tells his crew that the conditions are "tricky" with parts of it very damp and others very wet. Petrov posts 25.301 to leapfrog his Renault teammate.

With 23:50 remaining, Button goes fourth with a 25.183 despite a mistake at Turn 3. Still only 15 names on the timesheets.