What is the correct plural of "stadium"? [duplicate]

The correct usage would be stadiums.

Though most dictionaries disagree, Stadia in its strict sense is supposed to used only to measure lengths in excess of 1 stadium (which is equal to 200 metres approximately)

This is what Wikipedia says - "Stadium" comes from the Greek word "stadion" (στάδιον), a measure of length equalling approximately 200 metres. The oldest known stadium is the one in Olympia, in the western Peloponnese, Greece, where the Olympic Games of antiquity were held since 776 BC. Initially 'the Games' consisted of a single event, a sprint along the length of the stadium. Therefore the length of Olympia's stadium became somewhat of a standard measure of distance. A Roman stadium was slightly smaller, a distance of 125 passus (double-paces), equal to about 185 meters or 607 feet.

The English use of stadium comes from the tiered infrastructure surrounding a Roman track of such length. Although most dictionaries provide for both "stadiums" and "stadia" as valid plurals, etymological sticklers sometimes apply "stadia" only to measures of length in excess of 1 stadium.

http://en.wikipedia.org/wiki/Stadium#History_and_Etymology

Merriam-Webster gives both stadiums and stadia, so it comes to which one of them you prefer. Note, my Google Chrome doesn't know stadia and asks me to correct it :)