Chief executive of Hastings Pier Charity Simon Opie had hoped the structure would open in the spring or summer, but the date has been moved to 21 March next year.
He said storms in 2014 caused a significant amount of additional damage and pushed back the work.
The reopening will now be on the 950th anniversary of the Battle of Hastings.
Mr Opie said: "We're really disappointed not to be opening earlier.
"Almost all the work will be finished this year but not completed in time to open the pier during any of the traditional seaside trading months."
Local traders have spoken of their disappointment at the "frustrating" delays.
Joel Griggs of the New Crime Museum said: "It will effect us, definitely. We can't wait for the pier to open as it really will lift the area enormously and get the footfall going down here."
Kevin Boorman of Hastings Borough Council said: "What is the point of opening September, October, November time with winter coming up? Far better to open at the start of the visitor season."
The Victorian pier opened in 1872 but closed in 2006 amid fears it was unsafe.
The week before the fire in October 2010, architects were invited to submit designs to redevelop it.
Two teenagers were arrested after the blaze but the Crown Prosecution Service said there was not enough evidence to bring charges.
Most of the funds for the Â£14m scheme came from the Heritage Lottery Fund and more than 3,000 people also bought community shares in the company that will own and operate it.
Much of the existing pier is being recycled or reused, and plans for the redeveloped structure include funfairs, a circus, an open-air cinema and a mirrored heritage centre to reflect the seaside views.
A pier that was partly destroyed by fire in 2010 will reopen in 2016 - a year later than planned.