WORK on the £1.3 billion Queensferry Crossing has been halted for an average of two days a week since November because of bad weather.
Engineers behind the 1.7-mile structure – alongside the Forth Road Bridge – expected to lose 32 days to the weather in that period, but the actual total was 71.5 days.
Contractors are now under pressure to explain why the bridge’s programme didn’t make more allowance for bad weather.
The crossing is currently expected to open in May next year, five months later than previously stated by the Scottish Government.
Labour’s Transport spokesman Neil Bibby said: “No government or contractor can control the weather but there should have been much better planning for all eventualities.
“It looks like this project had very optimistic expectations for Scottish weather that have unsurprisingly not been met.
“It’s little wonder that the opening date for the bridge has been delayed by at least six months.
“Given there have been more than double the number of days lost to bad weather than expected, SNP ministers must confirm what discussions they have had with Transport Scotland about this and whether there will be any additional cost to the taxpayer because of the delays.”
Work to erect the cables on the bridge is affected by winds of more than 25mph and work to install the decking units is affected by speeds of more than 34mph.
Average wind speeds recorded on the neighbouring Forth Road Bridge show last year there were 158 days when the average wind speeds and gusts topped 30mph.
The year before, the tally was 142 and before that it was 131.
Alex Cole-Hamilton, Edinburgh Western Liberal Dem ocrat MSP, said: “Anyone who has seen a weather forecast will know that meteorology is not an exact science, but the fact that we have seen double the number of bad weather days than were forecast raises questions over where these numbers came from.
“The upshot of this failure of planning is that motorists are facing months more disruption and delays.”
A Transport Scotland spokesman said: “It is for the consortium FCBC to manage their resources throughout the period of the contract but we are aware of the actions that have been implemented by FCBC as required to mitigate any time being lost.
“In short, all that can be done has or is being done to achieve the earliest possible opening date to traffic but as we have stressed, no-one can control the weather.”
He added: “The Forth is a windy location and therefore FCBC’s deck lifting and cabling operations are ready to take advantage of relatively short weather windows.”