Wet conditions at the Yeongam circuit in Korea meant that McLaren's Lewis Hamilton used Pirelli's P Zero Blue intermediates to go quickest with a time of 1:50.828 in the second free practice session today. He was followed by his team mate Jenson Button, who was just a tenth of a second slower.

Some of the drivers attempted to run on the slick tyres later in the session, but it soon became clear that there was too much water on the track to set a time. The Yeongam circuit has not been used since the previous Korean Grand Prix in 2010, making the surface extremely 'green' and slippery, with no rubber being laid down. Ambient temperatures of 19 degrees centigrade also meant that the drivers struggled to get heat into their tyres.

With Friday characterised by wet weather from the start, all the teams were allocated an extra set of intermediate tyres as per the latest regulations. This meant that the drivers each had five sets of intermediates and three sets of rain tyres at their disposal for the day. During the morning session, all the drivers used the P Zero Orange wet tyres. Michael Schumacher went quickest for Mercedes with a time of 2:02.784 right at the end of the session when the track was beginning to dry in a few places.

The afternoon session started with light rain, which diminished slightly after about half an hour. All the drivers apart from Sauber's Kamui Kobayashi (who stuck with the wets) started the session using the P Zero Blue intermediate, before some of the drivers tried the P Zero Yellow softs and P Zero Red supersofts nominated for the race weekend.

With no dry running in the morning, the priority for the teams in the afternoon would have been to assess tyre performance on a dry track with varying fuel loads, in order to determine the crossover point at which it is best to change tyres. When this turned out not to be possible due to continued rain, the teams concentrated on assessing the relative performance of the intermediate and wet tyres. Drier conditions are expected for tomorrow and Sunday, meaning that tomorrow's hour-long final free practice will be crucial.

Paul Hembery: "The teams were given an extra set of intermediate tyres today, which along with the wet tyres performed well: there was a low wear rate that will enable them to do 20 laps or more in these conditions. After some of the drivers attempted to go out on the slick tyres this afternoon, it became clear that the track was just too wet to learn anything meaningful from them, particularly as the surface was slippery here even before it started raining. We've also seen that the circuit takes a long time to dry out, because of the characteristics of the asphalt and the lack of elevation. The initial indications are that tomorrow should be drier, so it's certainly a handicap not to have had any dry running today. However, it's the same for everybody and these are simply the challenges that form part of racing. Tomorrow, we hope to learn more about the performance of our slick compounds on this demanding track."