Ahead of today's opening session the air temperature is 16 degrees C, while the track temperature is an equally cool 16 degrees. We're at Spa-Francorchamps and it wouldn't be Spa without some of the wet stuff... and we don't mean beer.

It is not raining now, but overnight rain has left the track wet. There is heavy cloud but also some sunshine in the distance. That said, the session is officially declared wet.

Tyre options are hard (prime) and medium (option), while there are two DRS zone, the first on the short pit straight and the second on the Kemmel Straight leading up the hill to Les Combes. Detection points are before the chicane and the other on the run down to Eau Rouge.

There is only one reserve driver on duty this morning, Heikki kovalainen standing in for Charles Pic at Caterham.

Kimi Raikkonen, who was off sick yesterday, is one of the first out, along with Vergne, Ricciardo, Gutierrez and Bianchi, all are on Inters except the Marussia driver who is on full wets.

One by one the drivers take to the track and one by one, the installation lap completed, they head back to the pits.

While Bianchi says the track is drying quickly, the Williams duo insist that some corners are still very wet.

Less than ten minutes into the session everyone has been out, Vettel the last to do so. The German, like his possible 2014 teammate (Raikkonen) completes two laps.

Fifteen minutes into the weekend, Bianchi posts the first time of the day (2:07.578), as Bottas and Button join him. The conditions catch the Finn by surprise causing him to run over the speed bumps at Les Combes.

Button posts 2:00.510 with Chilton crossing the line at 2:05.891 moments later. The McLaren driver, told that it is raining in the pitlane and that more rain is expected, warns that another lap will damage the rears. The cameras pick up a beautiful slide from Bottas.

As Kovalainen is warned of more rain, the cameras switch to Vettel and his new blonde locks.

Raikkonen is back on track, Lotus running its passive DRS system, though its unclear when benefit or feedback they'll get from running it in these conditions.

Like Les Combes, the chicane - formerly Bus Stop - is catching drivers out, Grosjean amongst those caught out. It is the first and third sectors that are damp, the second sector is fairly dry. To prove the point Massa clams it is too dry in parts for Inters but too wet in others for dry tyres.