Ahead of today's opening session, the air temperature is 27 degrees C, whilst the track temperature is 37 degrees. It is bright though heavy rain is expected during FP2 and for much of the weekend.

Tyre choices this weekend are medium (prime) and soft (option), this being the third successive race at which this combination has been used.

There are two DRS zones, the first detection point is at the apex of T2, with activation shortly after T3, while the second has its detection point just after T13, with activation after T15.

In the wake of his accident in Monaco, and the subsequent admission that he has been partying too hard in recent weeks, no doubt all eyes will be on Lewis Hamilton.

Bearing that in mind, let's not forget that today is Friday the Thirteenth.

The fight for runner-up spot between Nico Rosberg and Sebastian Vettel should spice up the weekend, similarly the battle between Lotus and Toro Rosso for sixth in the constructors' standings - where points decide the prize money - not forgetting McLaren's bid to over haul Sauber. And ever expected to red that line?

Jolyon palmer replaces Romain Grosjean at Lotus, whilst Alexander Rossi is making his last appearance of the season, the American contesting the final round of the GP2 Series in Abu Dhabi in two weeks.

Ricciardo is running the upgraded Renault engine today - which means a ten-place grid penalty - though teammate Kvyat is sticking with the 'old' unit for this session.

The lights go green and Palmer leads the way, followed by Kvyat, Stevens, Bottas and Maldonado. Raikkonen, another early riser, is sporting a massive sensor device on the rear wing of his Ferrari. Alonso's McLaren also sports a number of sensors, though his are either side of the cockpit behind the front wheels.

After a brief lull, surprising considering the free tyre set and the prospect of rain later, Verstappen heads out, the Dutch youngster having made F1 history when he drove in FP1 here last year.

Fifteen minutes in, as Hamilton finally heads down the pitlane, Verstappen and Sainz post the first times of the weekend, the Dutchman (16.157) being the quicker of the two.

Verstappen spins in T3, bringing out the yellows for the first time.

He might have left it late coming out but Hamilton wastes no time in posting a time, the Briton goes quickest with a 15.102, ahead of Rosberg, Vettel and Button.

Hamilton and Rosberg both improve, third placed Vettel now 0.974s off the pace.

As Hamilton raises the bar with a 14.451, Raikkonen and Perez are the only drivers yet to post a time.

"I'm struggling massively with the overall grip on the car," complains Massa, a two-time winner here. He posts 16.395 to go 12th.

"My tyres are shot," says Button, the Briton subsequently told to pit.

As Ricciardo posts 15.209 to go fourth, Vettel closes to within 0.614s of Hamilton. Kvyat, running the old Renault engine, is sixth on 15.762.

A minor off at T5 for Maldonado (No 13, remember).

As the opening half-hour comes to an end and the drivers hand back their free set of tyres, Hamilton is quickest, ahead of Rosberg, Vettel, Ricciardo, Perez, Kvyat, Hulkenberg, Sainz, Button and Bottas. Raikkonen remains the only driver still to post a time.

Though the Mercedes duo are in a league of their own, as ever, the next 11 drivers are covered by just over a second.

"Plenty of interest around the Silver garage... what you lookin' at hmmm???" tweets Mercedes, amidst talk of an S-duct device on the cars.

Eventually it is Raikkonen who breaks the silence that hangs over the circuit, the Finn heading down the pitlane.

Despite a lock-up, Raikkonen goes third (14.997), albeit 0.546s off Hamilton's pace. He subsequently improves to 14.735.

Lots of activity in the Red Bull garage as the mechanics work on both cars.

Back on track, Verstappen improves to fourth with a 14.960, the Dutchman going quickest in S2 in the process.