Ahead of today's free practice session, the air temperature is 24 degrees C, while the track temperature is 31 degrees. It is bright and sunny but it is widely forecast that there will be rain later in the day, as was the case on Thursday and Friday.

While Fernando Alonso topped the timesheets on Thursday morning, it was Jenson Button who set the pace in the afternoon. That said, the Englishman was one of as handful of drivers - Kamui Kobayashi being one of the others - to run on the option (supersoft) tyres before the weather turned, consequently, that particular session wasn't really a good yardstick.

Generally, both Lotus and Ferrari are looking good here, with Pastor Maldonado keeping Williams in the mix. McLaren are up there, as are Mercedes, while Red Bull has yet to show its hand.

Assuming the race is dry - never a certainty in the Principality - Pirelli expects the soft tyres to last for around 50 laps and the supersoft to last for 35 laps, with a difference of about a second per lap between the two compounds.

What was really noticeable on Friday, even in the dry, was the lack of grip, drivers encountering all manner of problems on the green and greasy track. The problem is exacerbated by the fact that certain sections, particularly Mirabeau, have had new asphalt laid and this is catching drivers out on a regular basis.

Verge is straight out of the box when the lights go green, followed by Kovalainen - whose engine failure on Friday morning brought the session to an early close - Ricciardo, Petrov, Kobayashi, Karthikeyan, Hulkenberg and Alonso.

Three minutes into the session all but Hamilton, the Mercedes duo and di Resta have been out.

Raikkonen, who didn't complete a times lap on Thursday morning due to a steering issue, stays out for a second lap, the Finn clearly his Lotus all the way.

Locking up at various parts of the circuit, Raikkonen crosses the line at 1:21.612. Moments later, Schumacher posts 20.743.

Raikkonen improves to 18.993 while Schumacher posts 19.371, the pair subsequently leapfrogged by Rosberg and his 18.923.

Eight minutes into the session, with just three names on the timesheets, di Resta comes out for his installation lap.

Raikkonen, sporting his James Hunt helmet, ups the ante with an 18.039, with di Resta posting 18.125 to go second. As Schumacher pits, Raikkonen improves with a 17.865 only to be demoted when di Resta bangs in a 17.390.

Massive lock up for Rosberg going into the Chicane, scene of his, and Perez', accidents last year.

A sudden flurry of activity sees more than fifteen drivers take to the track, Grosjean immediately on the pace and going straight to the top of the timesheet (16.812). As the dust settles, Webber is fourth, ahead of Petrov and Hamilton.

With all but di Resta, Raikkonen, Rosberg and Schumacher on track, Grosjean goes quickest in all three sectors crossing the line at 16.359. Hamilton goes second with a 16.920 with Vettel slipping into third with a 17.002.

No surprises as Karthikeyan takes to the escape road at Mirabeau, the HRT driver having to perform a do-nut in order to extricate himself.

Perez goes second (16.642) as Grosjean begins another blistering lap, the Frenchman breaking into the 1:15s (15.811). Schumacher improves to fifth with a 17.032.

Onboard camera catches Perez deposit some rubber on the barriers in the approach to Rascasse, the Sauber driver subsequently pitting.

Massa improves to third with a 16.353 only to be demoted when his Ferrari posts a 16.340. However, the under-fire Brazilian hits back with a 16.070 to go second.

Proving Sauber's apparent strength at the circuit, Kobayashi goes fourth with a 16.311 as the McLaren duo remain seventh (Button) and eighth. The Williams duo are currently nineteenth and twentieth, but this should change, certainly for Maldonado, in the not too distant future.

Approaching half-time, Raikkonen is the first driver to switch to the option tyres. Elsewhere, Alonso improves to fourth (16.134).