The other is stormy conditions that stir up the oceans.
"As storms track northward they mix up the water that's beneath the surface that's also cooler and they bring that water to the surface
"When you combine these two factors it leads to some pretty chilly water temps around the beaches, especially in the North Island where people like to holiday at this time of year."
Noll said Auckland water is sitting around 18°C while the Coromandel is reading between 17°C and 17.5°C.
But all is not lost.
Noll thought that February should bring some more mild conditions as, "climatologically" water is at its warmest point.
"So hopefully we see that response as we head into the later stages of summer, and perhaps early autumn."