Ahead of today's second practice session, the air temperature is 17 degrees C, whilst the track temperature is 42 degrees C. It remains bright and sunny.

That said, the cool temperatures are providing drivers with a serious challenge as they are finding it difficult to get them into their ideal operating window. Furthermore, with the threat of rain and a further drop in temperature the situation is likely to get more problematic.

Lewis Hamilton topped the timesheets earlier, ahead of Rosberg, Vettel and Verstappen.

In a rare move, Williams opted to show its hand on a Friday, Valtteri Bottas finishing the morning sixth overall.

However, it wasn't all positive for the Grove outfit. A DRS issue saw Felipe Massa crash into the barriers at T1, and whilst the Brazilian was unhurt that was more than could be said of his car. Furthermore, concern as to the exact cause of the incident will be hanging over the team.

There were issues for McLaren as well, Jenson button suffering an oil leak which side-lined him for much of the session, and then a temperature issue arising when he finally made it back out.

Renault and Red Bull have upgraded engines for both drivers this weekend, whilst Ferrari and Honda have also upgraded their units. That said, the Renault duo are both over 3.6s off the pace.

Tyre options are ultrasoft, supersoft and soft, as in Monaco, whilst there are two DRS zones, the first on the straight leading to the final chicane that marks the infamous 'Wall of Champions', and the second on the pit straight just after said wall.

Hamilton posted his best time on the supers, as did Vettel, whilst Rosberg's best was on ultras and Verstappen's on the soft.

Talking of Verstappen, the Red Bull driver has been handed a reprimand for slowing unnecessarily in front of Bottas earlier.

The lights go green and Vettel joins the Manor duo in the rush to get out first. Raikkonen is also keen to get to work, like his teammate he is on the soft rubber.

Wehrlein posts 24.632 but this is soon beaten by Vettel who crosses the line at 17.815.

Bottas goes quickest in the first two sectors, before diving into the pits. The team, mindful of Massa's incident, check his rear wing.

As Hamilton goes quickest (17.564), Vettel has to cut the final chicane after coming up on a slower car.

No sooner has Vettel improved (16.711) than Hulkenberg posts a 16.533 and teammate Perez 16.203., both are on the softs.

Bottas goes fifth, despite being quickest in S1, as Hamilton and Button are the only drivers not on track.

As Kvyat goes third (16.287), Vettel momentarily goes quickest only to be toppled by Perez (16.065) again.

Sainz makes it a Toro Rosso 3-4 as he posts 16.205, the Spaniard on the red-banded supersoft rubber.

Moments later it's a Force India 1-2 again as Hulkenberg posts 15.944.

The Silverstone outfit's moment in the sun is short-lived as Verstappen slips in a 15.920 before he too is eclipsed by Vettel (15.897) and then Ricciardo (15.530).

Rosberg enters the mix with a 15.814 as Verstappen raises the bar with a 15.442.

Ericsson is the first driver to try the ultras this afternoon, the Swede subsequently posting 17.465 to go fifteenth.

Going quickest in S2 only, Hamilton nonetheless goes quickest overall, crossing the line at 15.343.

Meanwhile, McLaren has changed the engine in Button's car, the team reverting to the Monaco unit, though he still has the new turbo.

However, it's not all doom and gloom for McLaren, Alonso is currently 7th (15.945).

Going quickest in the first and third sectors, on the soft rubber, Hamilton is the first driver to break the 1:14s barrier, stopping the clock at 14.941.

Massa, on the ultras, posts 16.926 to go 12th. He subsequently improves to fourth (15.703).

Also on the ultras, Bottas posts 15.213 to go second, 0.272s down on Hamilton and two tyre steps.

Raikkonen has completed the most laps (20), the Finn currently down in 21st, 3.224s off the pace on the softs. Seemingly Ferrari has a cunning plan as its splits its strategy, sticking the Finn on a high fuel long run.

More and more drivers now switch to the ultrasoft rubber. Among them, Perez can only manage seventh (15.666), whilst teammate Hulkenberg posts 15.416 to go fourth.

Also on the ultras is Rosberg, who goes quickest in the final two sectors to post a 14.751. However, now Hamilton is on the purple-banded rubber.

Ominously Hamilton goes quickest in S1, maintaining the pace in S2. He crosses the line at 14.212, while Rosberg improves to 14.738.

Thirty-five minutes into the session, Button is finally back on track. His first lap sees the Briton post 24.854.

Check out our Friday gallery, here.