Ahead of today's first free practice session the air temperature is 19 degrees C, while the track temperature is 23 degrees. While bright, there is a lot of cloud.
Tyre options this weekend are medium (prime) and super-soft (option).
Thanks mainly to its Mercedes powerplant, McLaren is expected to have the edge here this weekend, though Red Bull will almost certainly be more than ready for the challenge. That said, with rain forecast on Saturday and Sunday, perhaps the weather gods have a surprise result up their sleeves.
While McLaren will also gain courtesy of its F-duct, surprisingly, Red Bull has opted not to run its version here, claiming that it still needs more work.
The lights go green and among the first group of drivers to go out are Vettel and Massa, with Webber also keen to get to work.
In the McLaren garage a couple of the mechanics are sporting dangly 'diamond' earrings, a clear dig at Hamilton's newly pierced ears.
Four minutes into the session, all but Hamilton and Schumacher have been out. Kovalainen is already complaining about a total lack of grip, comparing the Montreal track to a rally stage.
Five minutes into the session, Hamilton and Schumacher leave the pits, the Englishman waving to the crowd.
Ten minutes into the session, Hulkenberg is the first driver to go out for a second run, while in the Red Bull garage Webber is chatting amiably with Christian Horner. Barrichello and di Grassi head down the pitlane as Hulkenberg returns.
Rosberg and Glock are on track, and sixteen minutes in to the session it looks as though we are about to get our first timed lap. Maybe not… both drivers head back to the pits.
Thirty minutes into the session it is Kamui Kobayashi who finally gets thing going, the Istanbul point scorer crossing the line at 1:28.723. Shortly after, Alguersuari posts 25.265.
Nico Rosberg, who is still in the pits, is told that there is oil in the middle of the track at the final chicane.
As Hulkenberg and Senna leave the pits, Alguersuari raises the benchmark with a 23.415.
As Hulkenberg begins his first flying lap there are a few small spots of rain on the camera lens. Kobayashi goes quickest with a 22.581.
Buemi gets it all wrong at Turn 8, as Hulkenberg goes quickest with a 21.588. Elsewhere, a groundhog runs across the track, thankfully, Anthony Davidson is on duty at Le Mans.
Kobayashi goes quickest (21.311), but is quickly demoted by Hulkenberg (21.107) while Barrichello goes third.
Having gone quickest in the first two sectors, Barrichello does it again in the third, taking the top spot with a 20.276.
At half-time, it's: Barrichello, Hulkenberg, Kobayashi, Buemi, Alguersuari, Trulli, Kovalainen, Senna, Trulli and Chandhok.
Button and Webber are the first of the big guns to come out, as the begin their first flying laps, Hamilton and Schumacher leave the pits.
On his first flying lap, Button goes sixth (22.449), however, he is quickly demoted when Webber posts 22.107.
Button improves with a 20.683 to go second but is demoted again when Schumacher and then Hamilton (19.708) go quicker. Next time around Button posts 19.315 as Schumacher almost trips up over Petrov.
Vettel's first lap sees the German go fourteenth (21.974) as Schumacher takes the top spot with a 19.173. Moments later it is the McLaren-Mercedes of Hamilton that goes quickest, the Englishman breaking the timing beam at 18.571.
Lots of people getting it wrong at Turn 8 and having to cut the chicane and run over the grass.
Behind the top four, Alonso is fifth (19.668) and teammate Massa sixth, with Vettel now in seventh. Still no times from Glock or di Grassi.
An 18.885 sees Alonso improve to third behind the McLaren duo, as Kubica goes sixth with a 19.553. The Renaults are quickest through the main speedtrap.
di Grassi stops at Turn 7 bringing out the yellow flags. Looks like it could be another difficult weekend for Virgin.
Kubica posts 18.662 to go third, while teammate Petrov - currently twelfth - is clearly struggling. De la Rosa spins at the hairpin, the Spaniard looking vulnerable as he remains in his car facing the wrong way and cars passing on either side of him.
Schumacher posts 18.592 to go third, immediately going quickest in the first sector of his next lap. The German crosses the line at 18.285, thereby splitting the McLarens, just 0.158s off Button's time.
With twelve minutes remaining, Vettel is tenth, while teammate Webber is thirteenth, just ahead of Petrov. Once again, Lotus has the edge as far as the 'newbies' are concerned, with Hispania and Virgin pretty evenly matched.
A discussion between Massa and Rob Smedley regarding tyres, has the Englishman revealing that having seen the tyres via the rear facing camera, he can see that they're not in great condition.
Tonio Liuzzi, who is running an impressive seventh, is making major adjustments to his steering wheel. Indeed, he is so intent on adjusting something that he misses the chicane and takes to the grass.
Vettel improves to seventh, having posted a personal best in the final sector. Very early days but the Red Bulls are not looking quite so convincing here.
The session ends with Button quickest, ahead of Schumacher, Hamilton, Rosberg, Vettel, Kubica, Alonso, Liuzzi, Hulkenberg and Barrichello.
Sutil is eleventh, ahead of Massa, Petrov, Webber, Kobayashi. Buemi, de la Rosa, Alguersuari, Kovalainen, Chandhok, Trulli, Senna and Glock. di Grassi did not post a time.
Petrov was quickest through the main speedtrap, ahead of Kubica, Button, Massa, Alguersuari and Buemi.
Kobayashi completed the most laps (33), ahead of Hulkenberg (31), Senna and Alguersuari (28).