An early run from Jenson Button before the expected rain came down meant he finished Friday's first practice at Hockenheim comfortably in the P1 slot.
With the rain threatening, first practice for the German GP got underway as the two Toro Rossos led out the field - with many cars decked in aero or carrying aero devices - for their installation laps. However, it was Sauber's Kamui Kobayashi who posted the first time, a very slow 1:55.569.
That was, as to expected, easily beaten by Jenson Button as the McLaren driver got down to business in his revised MP4-27. He posted a 1:18.759, taking over a second off on his next lap. Button continued lapping, shaving tenths off his time as first Sergio Perez and then Romain Grosjean took second place.
The early running saw several drivers test the limits of the track and find themselves wanting as Heikki Kovalainen, Perez, Kamui Kobyashi, Kimi Raikkonen and Mark Webber - to name just a few - ran off the track.
Half an hour into the session the rain started to come down, prompting most of the field to return to the pits.
But, just a few minutes later, they were back on track with Button holding onto the P1 slot ahead of Grosjean and Perez. Jules Bianchi, Button, Kobayashi and Pastor Maldonado added their names to the list of those running off the track with the Williams driver having a long trip across the gravel before he headed back to the pits.
He was joined by the rest of the field as once again the rain came down, this time heavier than before, forcing the drivers back into their garages.
The rain, though, didn't last long and the action was soon underway with Ricciardo climbing to third place and Maldonado taking fifth. Surprisingly, though, except for Button none of the big-named runners were stamping their authority.
This changed in the final 30 minutes as Fernando Alonso, Lewis Hamilton, Nico Rosberg, Michael Schumacher and Sebastian Vettel also entered the top eight. None, though, were able to challenge Button for the P1 slot and moments later the rain again came down.
And although the drivers ventured back out in the final 15 minutes of the session and were able to improve their times, the third spate of rain meant Button's P1 time was safe with his team-mate Lewis Hamilton coming the closest to matching it, although still almost half a second down.
The session ended two minutes early for Valtteri Bottas as the Williams test driver touched the kerb into turn 12 and lost the rear end of the car through turn 13, spinning off the track, across the gravel and hitting the barriers with the rear of the car. He was okay. His crash, though, meant no one was able to put in a late challenge.
01 Jenson Button McLaren 1:16.595 27 laps
02 Lewis Hamilton McLaren 1:17.093 0.498 22 laps
03 Fernando Alonso Ferrari 1:17.370 0.775 21 laps
04 Michael Schumacher Mercedes 1:17.382 0.787 20 laps
05 Sergio Perez Sauber 1:17.413 0.818 28 laps
06 Nico Hulkenberg Force India 1:17.599 1.004 17 laps
07 Nico Rosberg Mercedes 1:17.915 1.320 27 laps
08 Felipe Massa Ferrari 1:17.995 1.400 22 laps
09 Pastor Maldonado Williams 1:18.020 1.425 20 laps
10 Romain Grosjean Lotus 1:18.130 1.535 21 laps
11 Kamui Kobayashi Sauber 1:18.226 1.631 22 laps
12 Sebastian Vettel Red Bull 1:18.339 1.744 21 laps
13 Valtteri Bottas Williams 1:18.422 1.827 28 laps
14 Daniel Ricciardo Toro Rosso 1:18.709 2.114 30 laps
15 Kimi Raikkonen Lotus 1:18.831 2.236 14 laps
16 Jules Bianchi Force India 1:18.972 2.377 21 laps
17 Jean-Eric Vergne Toro Rosso 1:19.039 2.444 34 laps
18 Vitaly Petrov Caterham 1:19.674 3.079 24 laps
19 Heikki Kovalainen Caterham 1:19.963 3.368 24 laps
20 Mark Webber Red Bull 1:20.122 3.527 27 laps
21 Charles Pic Marussia 1:20.169 3.574 20 laps
22 Timo Glock Marussia 1:20.539 3.944 18 laps
23 Pedro de la Rosa HRT 1:21.138 4.543 24 laps
24 Dani Clos HRT 1:21.740 5.145 27 laps