The Carefree Sundial, in Carefree, Arizona, was designed by architect Joe Wong and solar engineer John I. Yellott (1908–1986),^[1] was erected in the Sundial Circle plaza in 1959. The sundial is made from a steel frame and covered in anodized copper. As originally designed the 1200mm wide gnomon acted as a heat collecting plate for a local heating scheme. It measures 90 feet (27 m) in diameter. The metal gnomon, the shadow-casting portion of the dial, stands 35 feet (11 m) above the plaza and extends 62 feet (19 m).^[2][3] Local apparent time is 27.7 minutes behind the meridian time which here is Mountain Standard Time. The hour markers are adjusted accordingly.

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Carefree Sundial

Possibly once the largest sundial in the United States
33.8242°N 111.9220°W / 33.8242; -111.9220
Location	Sundial Circle Plaza, Carefree, Arizona.
Designer	Solar Engineer John I. Yellot and Architect Joe Wong
Material	Copper-clad
Length	62 feet (19 m) 90 feet (27 m) in diameter
Completion date	1959
Dedicated to	K. T. Palmer

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The Carefree sundial was conceived and constructed by John Yellott of Phoenix, Arizona, the architect was Joe Wong. The dial's gnomon is 4 feet (1.2 m) wide and 62 feet (19 m) feet long, rising 35 feet (11 m) above Solar Plaza. It is encircled by cacti and stones surrounding a reflecting pool with golden lines and concrete numbers to mark the time. Once it was visible from 3 kilometres (1.9 mi) but a shopping-centre has developed around it, obscuring the view. The hour-lines are offset to account for plaza's longitude, 6° 35' 36" west of the Mountain Standard Time meridian, 105° west. The gnomon served an ancillary purpose – designed to absorb solar energy which was converted into heat by three copper tubes, which pumped the heated water into a local heating system for a neighbouring office block. To facilitate the absorption the top 52 feet (16 m) of the gnomon's length is coated with a special paint. A smaller 1/48 scale model is on site along with an equation of time table.^[4]

Various communities have made "the largest sundial in" claims. In 1913 the sundial in Ingleside Terraces, San Francisco was claimed to be the largest in the world,^{[5][lower-alpha 1]} ignoring the existence of the dials at Jaipur. It had a dial diameter of 35 feet (11 m). There is even a larger one (78 feet (24 m)) at Hunters Point in San Francisco.^[7] The Carefree claim is disputed by Sun City, Arizona, who have repaired their competing dial which is built from a 64 feet (20 m) steel I-bar.^[8][3]