Hamilton, champion in 2008, looked strong from the get-go
Lewis Hamilton set the pace in treacherous conditions on Friday, topping times in both opening practice sessions ahead of this weekend's Hungarian Grand Prix, the last race before Formula One's mid-season break.
The 27-year-old was quickest for McLaren in the morning free practice session as the teams found their bearings and then repeated the feat in a rain-hit afternoon session which saw seven-time champion Michael Schumacher crash in his Mercedes.
Hamilton's best time of one minute and 21.995 seconds came before the rain hit the Hungaroring circuit midway through the afternoon session after he and McLaren team-mate and fellow-Englishman Jenson Button had dominated in the morning.
Finn Kimi Raikkonen was second fastest for Lotus ahead of Brazilian Bruno Senna for Williams and the two Ferraris of Brazilian Felipe Massa and championship leader Fernando Alonso. Hamilton's McLaren team-mate Jenson Button was sixth.
Defending world champion Sebastian Vettel of Germany was eighth for Red Bull after failing to clock a fast lap on soft tyres and Schumacher, 43, was 10th.
Schumacher's Mercedes team-mate and fellow-German Nico Rosberg was 11th and Australian Mark Webber, in the second Red Bull, was down in 14th.
Hamilton set his time in the fastest part of the day when clouds gathered after a hot spell shortly before the rain fell.
Earlier, several drivers had set the early pace including Finn Kimi Raikkonen of Lotus and championship-leading Spaniard Alonso of Ferrari.
Schumacher lost control of his car during the wet spell at turn 11 where he ran off straight into the barriers. He was unhurt and climbed out before walking clear.
Hamilton, without a contract agreed for next year, was in fine form and continued setting fast times when the rain began to fall before his team pleaded with him to come in and avoid any risks in the hazardous conditions.