Ahead of today's second practice session, the air temperature is 23 degrees C, whilst the track temperature is 33 degrees.

As has become the norm, the Mercedes set the pace this morning, Lewis Hamilton a full 0.415s clear of his teammate. Third quickest was Romain Grosjean, the Frenchman 1.509s off the Briton's pace.

The threatened rain never made an appearance which meant that the teams were able to stick to their initial programmes and not need to bring forward the introduction of the option (supersoft) rubber.

As ever grip was a problem, with a number of drivers spinning, including pace-setter Hamilton running wide, locking up and spinning. Indeed, Hamilton's 180 degree spin was at the hairpin, right in front of his teammate.

As expected, brakes could be an issue here, the Circuit Gilles Villeneuve being one of the toughest tests of the year. Which could mean bad news for Mercedes and Lotus, in particular.

Whilst almost all the teams have brought updates, it is far too early to see whether the engine upgrade at Ferrari has made any in roads in to Mercedes advantage, hopefully we will get to see the results over the next 24 hours. However, with Mercedes-powered cars filling six of the first eight positions this morning, Ferrari has its work cut out.

Whilst the rain didn't make an appearance this morning, it is expected that we could see some wet stuff over the next ninety minutes - the ominous dark clouds heading towards the circuit seeming to confirm this. Indeed, Renault claims there is a 70 percent chance of rain.

The lights go green and with an eye on the weather the big guns, including Vettel and Rosberg are eager to get to work. The Ferrari driver is already on the option rubber, as is his teammate. Thing is, is it warm enough for the softer rubber at this stage?

As Vettel posts 1:21.855, the Force India duo are also on the option rubber. Everyone else is on prime (soft). Raikkonen posts an impressive 17.793, as Rosberg goes third with a 24.815.

Next time around Vettel posts 16.534 as Rosberg goes second (17.215).

Hamilton complains of a vibration in his current set of tyres. The Briton can only manage 23.894.

Raikkonen now looks set to improve, the Finn going quickest in the first two sectors. At the line the Ferrari driver posts 16.686 to go second, whilst his teammate raises the bar with a 16.304.

Hamilton has to use the escape road at the final chicane when Grosjean slows to a crawl leaving the Briton with no other option.

Now on the softer rubber, Rosberg goes quickest in S1, though in S2 he can only manage a PB. At the line the German posts 16.440 to go second.

Hamilton is back on track, now on the options, all top five positions now filled by drivers on the red banded tyres.

As Race Control says that rain is expected at 14:35, Raikkonen posts 16.310 to leapfrog Rosberg.

Kvyat goes fourth and Grosjean fifth, both on the harder rubber, whilst Hulkenberg heads back to the pits having suffered a puncture. Whilst it looks as though he may have brushed the wall, the German insists he didn't hit anything. Whilst he says it was "just a puncture", the damage to the tyre is worrying.

Ricciardo (option) goes fourth (17.111), whilst a mistake in the final chicane means Hamilton fails to improve despite being quickest in the first two sectors. Slo-mo replay shows the Mercedes with all four wheels in the air as it rides the kerbs, the Briton lucky not to get up close and personal with the dreaded Wall of Champions.

A 15.988 sees Hamilton take the top spot, 0.316s clear of Vettel. All but the Lotus duo have posted times on the option rubber now.

Race control says that the rain is now expected at 14:30 - just over thirteen minutes away.

It's currently, Hamilton, Vettel, Raikkonen, Rosberg, Bottas, Kvyat, Ricciardo, Grosjean, Ericsson and Hulkenberg.

Now on the softer rubber, Grosjean improves to sixth (16.864), whilst Maldonado can only manage thirteenth (17.419). Massa goes ninth with a 17.151.

Raikkonen is told that when the rain arrives it will hit the track at T8. He subsequently switches to the prime rubber.

Maldonado improves to fifth with a 16.755.

"I have some hesitation with my engine," complains Raikkonen.

Nasr is told that the rain should arrive in five minutes and that he should remain on track for now.

"After careful investigation, we specify that Hulkenberg's left rear trouble is NOT tyre related," says Pirelli. "It appears to be rim related."