Notes: In researching this I found a surprising amount of dispute over the proper pronunciation of Hawaii. All agree that there are 3 syllables, but differences exist on how to pronounce the last two syllables.
There are three primary questions:
Does the middle syllable begin with a -w- or a -v-?
Does the middle syllable rhyme with sky or spa?
Does the last syllable begin with -y- and sound like yee?
The American Heritage Dictionary lists huh-WAH-ee as primary with huh-WY-ee and hu-VAH-ee as alternates.
Longman's Pronouncing Dictionary has huh-WAH-ee.
Mirriam Webster's Geographical Dictionary lists 3 pronunciations with huh-WAH-yee as primary and huh-WAH-ee, huh-VAH-yee as alternates.
The Big Book of Beastly Mispronunciations has huh-WY-ee or huh-WAH-ee as correct.
There seems to be a lingering debate over whether locals in Hawaii pronounce the second syllable beginning with a -v- or -w-. There is a persistent idea that locals in Hawaii pronounce the syllable beginning with a -v-.
In American Usage and Style: The Consensus (1980) Roy H. Copperud disputes this idea and says-- "[huh-VY-ee] is thought by some to be based on based on the correct native version. This idea has been knocked down, however, by two authorities as wrong (Introduction to the Hawaiian Language, by Judd, Pukui, and Stokes; and the Rt.Rev.Harry S.Kennedy, Bishop of Hawaii".
Mr. Ross confirms this in his article and confirms that in day-to-day use most locals in Hawaii pronounce the syllable with a -w-. Mr Ross says-- "The pronunciation [huh-VAH-ee] is a misunderstanding (in tourists) or an affectation (in locals -- though the sincere impression that /v/ is 'correct' is common)".
Rhyme with 'spa' or 'sky'?
Some of the authorities consulted list both WAH and WY as valid pronunciations for the middle syllable, but overall huh-WAH-ee seems to be preferred. In practice, both sound very similar and may be nearly be indistinguishable.
ee or yee?
Is the last syllable -ee or -yee? Hawaii is properly spelled Hawai'i where the apostrophe indicates what is called a glottal stop. A glottal stop is a momentary pause in the flow of air, like between the syllables of the interjection uh-oh. The correct pronunciation is huh-WAH-ee with a glottal stop. The pronunciation huh-WAH-yee is a common, but somewhat anglicized pronunciation.