(CNN) -- In the South Pacific Ocean east of New Zealand, satellite imagery shows a massive area of ocean water at well-above-average temperatures.
The water in the area is about 5 degrees Celsius (about 9 degrees Fahrenheit) "warmer than average for the latitude and time of year," said James Renwick, a professor and head of the School of Geography, Environment and Earth Sciences at Victoria University in Wellington, New Zealand.
The hot blob on the Pacific surface is detectable from space and is the largest area of above-average water temperature on Earth right now.
The patch of sea is about a million square kilometers (400,000 square miles), covering an area of ocean larger than the size of Texas.
"The ocean surface doesn't vary that wildly," Renwick said. "One degree (Celsius) is big. So, five degrees is huge."
It's especially rare to see over such a large area, but scientists say global climate change is making these phenomena more common.
Warm spot caused by recent weather
"The ocean surface does what the air above tells it," Renwick said.