The plan was to place the first three foundations Â— each weighing 700 tons (635 metric tons) and standing some 147 feet (45 meters) high Â— by the first week of September.
But the wind they hope eventually to reap is causing construction setbacks, and ocean waves are cresting too high.
"We've had a really, really shocking summer," said Jonny Stokes, a spokesman for E.ON AG, one of three energy companies partnering in the project. Vattenfall Europe and RWE are the two other participants.
Crews are waiting for a four-day block of good weather to install the three foundations for the first of 12 five-megawatt turbines nearly 28 miles (45 kilometers) off the shores of Borkum Island in the North Sea.
The project is farther offshore than any other wind farm and in deeper waters Â— factors that have worked against it.
"Offshore conditions are challenging," Stokes said, but insisted the benefits were still significant.
"The consistency and quality of the wind is better further offshore. You get a better load factor for the turbines," he said.
Stokes was optimistic about the project though, given the construction hazards.
"This is technically difficult," he said. "It's basically a pioneering project in the sense that it is in deep water and so far offshore."
The window for setting the foundations will close in October. If they can get the first three foundations installed by October, then the first phase should be on track to finish by spring or summer of next year.
So far, onshore work has gone according to plan, said Lutz Wiese, a spokesman for Vattenfall.
The foundation for an onshore transformer station is up, and work to erect the offshore transformer station Â— which only needs a 36-hour window for construction Â— is slated to start in mid-September.