Kimi Raikkonen continued his fine start to the 2013 season by setting the fastest time in second practice ahead of this weekend's Malaysian Grand Prix.
Raikkonen's time of 1:36.569 was set on the medium compound tyres - this weekend's option tyres - shortly before a heavy shower affected parts of the circuit.
Sebastian Vettel was just 0.019s down on Raikkonen, while the Ferrari's of Felipe Massa and Fernando Alonso were third and fourth.
Morning pacesetter Mark Webber was fifth in the sister Red Bull.
Rain arrived an hour into the session but did not last long, leaving drivers to head back out onto the circuit on Intermediate tyres. McLaren's Sergio Perez had a minor off, while Esteban Gutierrez struggled on the full wet compound before heading out onto Intermediates.
Gutierrez also had an unusual issue when the fire extinguisher in his Sauber C32 went off, forcing him to enter the pits.
Team-mate Nico Hulkenberg had a spin at the pit entry as conditions worsened while the Caterham racers Charles Pic and Giedo van der Garde also pirouetted in the damp weather.
Force India drivers Paul di Resta and Adrian Sutil were eighth and tenth, although Sutil suffered a mechanical issue in his car which left him in the garage for the final part of the session.
McLaren endured another difficult day as neither Perez nor Jenson Button set a quick enough time for the top ten.
It was another impressive session for Marussia rookie Jules Bianchi, who was just 2.9s down on Raikkonen's best time.