Michael Schumacher's Mercedes throws up spray during practice at Hockenheim yesterday. Picture: AP
The second 90-minute session at Hockenheim, especially, fell victim to the conditions, leaving Jenson Button out in front as he was quickest in first practice that stayed predominantly dry.
He led a McLaren 1-2, offering the team a degree of hope ahead of the weekend as the car has a raft of new updates on board designed to narrow the gap to their rivals.
Some are more visual than others, in particular new side pods to assist with aero-dynamics, as McLaren seek a boost ahead of the summer break following next weekend's race in Hungary.
Determined to put behind them the disappointment of the British Grand Prix in which Hamilton and Button were eighth and 10th respectively, the latter started the day off on the right foot with a time of 1min 16.595sec, with the former 0.498sec adrift.
By comparison, given the rain that dominated FP2, the best time posted by Williams' Pastor Maldonado was nearly 11 seconds down, with a lap of 1:27.476.
Heavy rain just before the start of the session kept everybody in the garage for the opening 25 minutes, other than an installation lap from Bruno Senna in his Williams.
That was simply a shakedown to assess the car given the minor damage sustained at the end of FP1 when reserve Valtteri Bottas spun into the gravel and clipped a tyre wall in Senna's car.
It was only when the rain finally stopped and the track began to dry a little did the times fall, with Maldonado at the head of affair when the heavens opened again 27 minutes from the end.
It did ease late on, but not enough for the track to offer up hope of anyone dislodging the Venezuelan, who was fastest by just 0.088 from Mercedes' Nico Rosberg.
Michael Schumacher, Rosberg's team-mate, brought out the red flag – it ended the session with four minutes remaining – when he ploughed into a tyre barrier in the stadium complex.
With the front and rear ends of the car damaged given the way he spun around upon impact, his mechanics face a long night carrying out repairs ahead of today's quali-fying session.
It was a rookie mistake from the seven-times world champion as he conceded: "The way I ended the second session was obviously not part of the plan.
"I'm sorry my mistake has given my guys even more work to do this evening.
"I simply slid off track because I lost a little concentration. We were talking on the radio and I was altering some settings at the same time."
On-board footage, however, undermines Schumacher as it shows him with both hands on the steering wheel at all times leading up to his crash.
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