The opening of the bridge has been delayed again because of “adverse weather conditions”.
Economy Secretary Keith Brown told MSPs on Wednesday the expected opening date would now between mid-July and the end of August.
Mr Brown was updating the Scottish Parliament’s rural economy and connectivity (REC) committee.
The £1.35bn megastructure was originally due to open in December last year but that date was postponed because of “strong winds”.
The minister said the latest problems were due to strong winds hampering the dismantling of the tower cranes and other ongoing activities.
He said: “Today there are only nine weeks remaining to the end of May and the review has concluded that even with the best weather this date is not now safely achievable.
“There is no additional cost to the public purse and the Forth Road Bridge continues to carry traffic over the Forth during these final weeks of construction.
“While its clearly very disappointing the new bridge won’t be ready ahead of the contractual completion date, I believe it is important to take the time to make sure the bridge is built in the safest possible circumstances to the highest possible standards.”