Sea temperatures off Raglan are currently at least 1°C warmer than the 36-year average.
"The warmer than average temperatures are noticeable - both for swimmers and for the ecosystem," states MetOcean Solutions Forecast Manager Dr Rafael Soutelino. "The warming could be caused by more sunny days than usual or by an onset of warm water residual coastal circulation from the north."
"Historically, the 20°C barrier is broken late December or early January off Raglan," explains Rafael. "However, if the current pattern continues, the water will reach 20°C much earlier than normal."
The warming pattern is not mirrored further south. In New Plymouth, water temperatures are recovering from upwelling of colder bottom waters which occurred in connection with the latest stretch of winds from the west - southwest.
"The sea surface temperatures do vary quite a bit from year to year," says Rafael. "The main variation is caused by the spatial location of different water bodies - so the warming of Raglan temperatures could be just a warm water body coming down earlier from the north. And although the current warming is pronounced, it could change quickly if prolonged southerly winds push colder waters up to Raglan."