Europe's first artificial surf reef off the Dorset coast will not now be completed until next year.
The project off Boscombe had already been delayed but work has now been suspended until April 2009.
Bournemouth Borough Council blamed the decision on the shorter days and weather conditions, and now hopes to open the £2.68m reef in September 2009.
Construction firm New Zealand-based ASR Ltd said its divers were struggling in the colder conditions.
The project has been beset with problems since construction started behind schedule in the summer.
In a statement the council said: "The shorter days and winter weather do not permit long enough working sessions for safe and effective construction on this major underwater project.
"Difficult weather conditions over the summer months brought about a later than anticipated start to the project.
"This has inevitably had a knock-on effect to the anticipated completion date, and ASR believes that the expected weather conditions will make it impossible to complete the reef this year, as originally planned."
The reef site is 225m (740ft) out to sea, east of Boscombe Pier and covers the size of a football pitch.
The structure, which will double the size of waves, is part of a £9.5m area redevelopment.
Dr Shaw Mead, from ASR, said: "Although conditions recently have been good and the base layer has been completed to design, the late start to construction has really set us back.
"The days now are short, the sea temperature is getting colder and there are stronger currents, meaning we have to limit the amount of time our divers can spend underwater."
The base layer has been completed, and Dr Mead said the unplanned delay would allow it to "settle" into the seabed.