Romain Grosjean set the pace in Saturday's final practice having jumped ahead of the two Ferraris moments before the rain came down.
With rain in the air the drivers were quickly down to business with Mark Webber taking the early P1 slot with a 1:30.978. Charles Pic was second ahead of Giedo van der Garde, Adrian Sutil and Jenson Button. On only his fourth lap the McLaren driver was heard complaining to his team about "graining" with his tyres, a major concern for McLaren.
Back at the front Toro Rosso's Daniel Ricciardo and Jean-Eric Vergne both had a brief foray into the top spot before being overhauled by the Ferraris, first Fernando Alonso, Felipe Massa and then Alonso again. The Spaniard lowered the benchmark to a 1:27.000 as he was told to expect rain in the "next 10 minutes."
Romain Grosjean, running major set-up changes to Friday, was the next to hit the front as the Lotus driver posted a 1:26.929 just as a few drops of rain began to fall. Brollies came out and raincoats quickly went on.
Four drivers had not set lap times when the rain came down: Lewis Hamilton and Pastor Maldonado, both of whom had gone out for three installation laps, Valtteri Bottas, who had done two, and Max Chilton, who managed just a single lap.
15 minutes after the last car pitted, Massa headed out on the full wets. With the Brazilian safely completing a lap others ventured out before everyone barring the two McLarens are lapping on the wet track. Hamilton, Maldonado, Bottas and Chilton all completed timed laps but as to be expected were 20 to 26 seconds down on Grosjean's best in the dry.
Sebastian Vettel's session came to a premature end when, with ten minutes remaining, he was told "do not shift, you've lost hydraulics" and with that he stopped on the side of the track. The team later billed it as a "precautionary measure" due to an "electrical problem."
Back in the action the drivers switched to intermediate tyres as the track began to dry out. However, it was still too wet to make any impact on the timesheets - although several drivers made impacts on the grass as they ran wide - and Grosjean ended with his first P1 of the campaign. Alonso was second ahead of Massa.
01 Romain Grosjean Lotus 1:26.929 14 laps
02 Fernando Alonso Ferrari 1:27.000 0.071 7 laps
03 Felipe Massa Ferrari 1:27.241 0.312 10 laps
04 Paul di Resta Force India 1:27.533 0.604 9 laps
05 Kimi Raikkonen Lotus 1:27.625 0.696 12 laps
06 Daniel Ricciardo Toro Rosso 1:27.849 0.920 19 laps
07 Jean-Eric Vergne Toro Rosso 1:27.860 0.931 16 laps
08 Adrian Sutil Force India 1:28.069 1.140 15 laps
09 Nico Hulkenberg Sauber 1:28.253 1.324 18 laps
10 Esteban Gutierrez Sauber 1:28.253 1.324 20 laps
11 Nico Rosberg Mercedes 1:28.486 1.557 13 laps
12 Sebastian Vettel Red Bull 1:29.808 2.879 9 laps
13 Mark Webber Red Bull 1:30.073 3.144 16 laps
14 Jules Bianchi Marussia 1:30.388 3.459 17 laps
15 Giedo van der Garde Caterham 1:30.598 3.669 20 laps
16 Charles Pic Caterham 1:30.959 4.030 19 laps
17 Jenson Button McLaren 1:33.236 6.307 7 laps
18 Sergio Perez McLaren 1:33.527 6.598 8 laps
19 Pastor Maldonado Williams 1:39.232 12.303 13 laps
20 Valtteri Bottas Williams 1:39.779 12.850 13 laps
21 Max Chilton Marussia 1:42.872 15.943 13 laps
22 Lewis Hamilton Mercedes 1:47.246 20.317 9 laps