This situation is expected to last till November or December, with temperatures hovering around three to six degrees Fahrenheit higher than normal.

The timing could not be worse as the corals in the area are just recovering from a mass bleaching event last year. Most have recovered since then.

"You go from a vibrant, three-dimensional structure teeming with life, teeming with colour, to a flat pavement that's covered with brown or green algae," said Ruth Gates, director of the Hawaii Institute of Marine Biology.

With the higher temperatures this year, it would be more difficult for the bleached corals to recover. "You can't stress an individual, an organism, once and then hit it again very, very quickly and hope they will recover as quickly," said Gates.

Bleaching occurs when higher temperatures cause corals to expel algae which they rely on for food. This makes the coral more prone to disease and increases the risk of them dying. This has implications for both the marine animals that live and spawn in the coral reefs, as well as the tourists who visit Hawaii for a dive holiday.

According to Chris Brenchley, a meteorologist from Honolulu's National Weather Service, it is not known why this year's higher temperatures around Hawaii and in other parts of the northeast Pacific are warmer than normal this year.