NEW YORK (CNN) -- Weather has delayed the scheduled Monday morning delivery of the final two sections of a 408-foot spire to the top of One World Trade Center, according to the Port Authority of New York and New Jersey.

The two sections were scheduled to be delivered to the roof deck, as long as weather allowed on Monday. Once they are installed, they will make the building the tallest in the Western Hemisphere, according to the site's management.

The two pieces form a stainless steel beacon weighing almost six tons and will be the final piece put in place to give the building an iconic height of 1,776 feet, according to a news release from the Port Authority of New York and New Jersey.

Once the architectural structure is complete, it will be comprised of 18 separate sections of steel and three communication rings. The first -- and heaviest -- steel section was installed in January, weighing more than 67 tons, the news release said.

Port Authority Assistant Director of Media Anthony Hayes said the original design included a radome -- short for radar dome -- but that was rejected because of anticipated servicing and maintenance difficulties. The radome would not have impacted the height, but would have provided an additional design element, which ultimately proved impractical, Hayes told CNN.

The spire will serve a television broadcast facility housed in One World Trade Center, the press release said.

While under construction, One World Trade Center became New York City's tallest building a year ago, standing 1,271 feet above street-level. The building then was 21 feet higher than the Empire State Building's observation deck.

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