‘Severe’ marine heatwave to hit South Island watersWest Coast waters are set to reach 18.4C this week. (File photo)The water temperature in the South Island is set to soar this week as a marine heatwave sweeps the West Coast. It’s expected to reach a whopping 18.4C – five degrees hotter than the average water temperature for this time of year. A marine heatwave is when water temperatures stay in the warmest 10% of what has been historically observed for at least five days. “Last year, a similarly warm marine heatwave in Fiordland reached great depths and caused widespread bleaching of sea sponges,” he said.

Source: Stuff January 02, 2023 02:11 UTC