Valtteri Bottas headed the time sheets in a washed-out final practice session for the French Grand Prix.
The Mercedes driver posted a best effort of one minute and 33.666 seconds in the opening moments before a heavy downpour at the Paul Ricard Circuit.
Defending champion Lewis Hamilton, who topped both practice sessions here in the dry on Friday, was among those who did not set a competitive lap.
Renault's Carlos Sainz was second in the order ahead of the Sauber of Charles Leclerc. The inclement
weather could yet play a role in qualifying which takes place at 4pm local time.
Hamilton, boosted by a new Mercedes engine this weekend, is bidding to move back ahead of Sebastian Vettel after losing his championship lead at the last round in Canada.
Ferrari driver Vettel heads Hamilton by just one point with 14 rounds still remaining.