Ahead of this morning's free practice session the air temperature is 15 degrees C, whilst the track temperature is 30 degrees. Yesterday's dark clouds have given way to the white fluffy kind and bright sunshine.

As expected, Mercedes pretty much rules here - ironic really considering we're at the Red Bull Ring - with Nico Rosberg quickest in the morning and teammate Lewis Hamilton doing the business in the afternoon.

With a 0.9s advantage over their nearest rival (Alonso) one would be forgiven for thinking the weekend is a lost cause but let's not forget that Canada showed there is a chink in the Mercedes armour even if Toto Wolff says the Montreal problem has been resolved.

Then again, graining looks likely to be an issue here as does the problem of keeping the cars on the black stuff, virtually everyone one going off at some point or another yesterday.

From the outset, the Ring has shown us that not only is it located in beautiful surroundings it is a circuit that demands total respect and those that fail to learn will pay the price.

As in Canada, Williams looks mighty strong, the Grove outfit ahead of the Red Bulls, McLaren and Toro Rossos indeed, other than the Mercedes, only Alonso was quicker.

That said, behind the Silver Arrows the next nine cars were covered by just 0.504s.

Possibly more than any previous race this season, tyre management is going to be a major factor, for despite the standings on the timesheets some teams are doing a better job with their rubber than others, something that will only really become apparent on Sunday.

Despite his, and his team's best efforts, Sergio Perez' grid penalty stands, the Mexican failing to have his five-place grid penalty overturned.

The lights go green and Sutil leads Massa, Chilton, Raikkonen, Vergne, Maldonado and Ericsson.

While most complete a single installation lap a couple complete two, however, nobody looks ready to post a time just yet.

That said, Magnussen posts a 15.696 to get the session properly underway, Rosberg posting 12.987 moments later.

As the pair trade times, Hamilton, Hulkenberg, Ericsson and Maldonado join in the fun.

As one might expect, Maldonado is one of the first to run wide, Hulkenberg also going off moments later.

"No engine braking at all," complains Button after running wide in T1, referring to his brake by wire. He dives into the pits with smoke pouring from the rear brakes.

The Briton is clearly unhappy that his team hadn't picked up on the issue, admitting that though there is a problem they weren't picking it up on the data feed. Elsewhere, Sutil is struggling with his front brakes.

Bottas goes quickest (10.641), ahead of his teammate, with Kvyat third, ahead of Magnussen, Raikkonen and Vergne.

With 38:00 remaining all but Perez, Alonso and the Bulls have posted times.

As drivers continue to struggle to remain on track, turns 8 and 9 particularly causing problems, it's worth noting that Charlie Whiting has warned that drivers straying too far off track at T8 in qualifying risk losing their times.

At the top of the timesheets, Bottas and Massa trade times however, there remain concerns as to the team's tyre wear.

As Alonso goes third (10.565), Vettel posts 12.151 to go thirteenth. Ricciardo is on track.

On the half-hour, Hamilton and Rosberg are ninth and twelfth, clearly biding their time.