ESPN rounds up all the reaction from up and down the paddock after Friday practice at the Circuit of the Americas.
Mercedes
Lewis Hamilton: "It's been a beautiful day... I love it when it rains! Just not on practice day! The weather has just been unbelievable. I don't think I've ever seen rain like this. It's kind of cool to watch, in many ways, but I feel terrible for all the fans who turned out today. I didn't complete many laps in the morning as the track was drying out and I wanted to save my tyres for the afternoon session - but in the end we didn't get to go out.