Defending champion Alinghi picked the Spanish port city for its consistent wind after the last America's Cup in Auckland was blighted by erratic breezes.

Now, the choice has come under scrutiny after a lack of wind has resulted in the round-robin stages of the Louis Vuitton Cup being rescheduled twice.

"Of course, you can see from the data that this has been an exceptionally bad month, it has been unlucky, but any venue at any time can suffer from this sort of thing," Alinghi meteorologist Jon Bilger said on Wednesday. "The weather is the weather after all, and it is uncontrollable."

Alinghi skipper Brad Butterworth was more blunt.

"We don't want to sit up here everyday and put the clubs in the car and play golf," he said. "But that's the way it is."

The challengers' series resumed on Tuesday after only three of a possible 16 flights had been raced with six days missed. The second stage, originally expected to begin Wednesday, has until May 9 to finish.

"This April is very unusual in the sense that we have an atmospheric block over Europe which is not atypical, but it is a particularly strong block and the position of it is what is causing these weak winds over Valencia for a prolonged period," Alinghi weather expert Jack Katzfey said.

AC Management wouldn't release weather data on Valencia, so the Swiss team, which conducted the analysis, did its own research. After analysing the weather buoys on the northern 'Romeo' course for wind in the afternoon when racing is scheduled, sailing has only been possible for half the number of days in April.

That is well down on the average of 80% to 90% of days being suitable for sailing from April through July since 2000.

"We still stand by our analysis that Valencia is a good sailing venue, it should not be judged on a single meteorological event," Bilger said.

But Valencia's Meteorological and Climate Center head, Jose Angel Nunez, said the event should have started in May to avoid possible scheduling problems.

"The wind that the competition is looking for won't be arriving until June and July," he said. "Winds are frequent in spring but not established until the summer, when they will be much more consistent. There's a better probability, frequency and intensity of wind the closer we get to summer, when you have the better atmospheric conditions for racing - it's evident."

Butterworth said the schedule wasn't only determined by the wind.

"The timing of the Cup was set certainly to fit into the market of television and then other events earlier and later in the year that could conflict with it," Butterworth said, referring to cycling's Tour de France.

Alinghi races the winner of the Louis Vuitton Cup in the America's Cup from June 23 to July 4.