Monday's post-race MotoGP test session at Estoril in Portugal has been cancelled.
As feared, heavy rain began falling during the night and - along with thick fog - continued into Monday morning's planned start to testing.
The rain, combined with poor visibility, meant the decision was taken to scrap the test.
Ducati had been planning to try a new engine with a smoother power delivery at the test, which was to be the first official chance for test time since the start of the 2012 racing season.
The test is expected to be rescheduled, although the date and location is still to be decided.
Round four of the 2012 MotoGP Championship will be held at Le Mans, France on May 18-20.