Mark Webber was left frustrated by the weather conditions during Friday's practice for the Australian Grand Prix.
The Red Bull driver, third quickest in the afternoon session, said the mixed conditions made things a nightmare for the teams, who are unable to learn anything about the tires.
"It wasn't too bad today," said the Australian. "Everyone's programs were disrupted in P2 with the intermittent weather.
"It's pretty much the team's worst nightmare when the weather's just on the edge like that; you can't commit to learning too much in the wet and it's quite tricky in the dry as well. We had a couple of windows where we got some information, though, so we have good data to go through tonight."
Sebastian Vettel finished down in 16th position after going off track in the final moments of the second session.
"I had a drift off track at the end of the second session; obviously it wasn't ideal, but it happens – that's what practice is for," Vettel said. "It was my mistake; I was a bit too far to the left when hitting the brakes.
"It meant I missed the most important time on the track at the end of P2, but the car feels good and Mark showed that we are right there. It looks very close between the top cars."