Guide
What is a temperature break?
A temperature break is the line where warmer and cooler water meet at the sea surface. On a sea surface temperature map it shows as a sharp change of colour.
How a satellite sees it
Infrared satellites measure the temperature of the very top of the sea. They can only see it where the sky is clear. Gap-free analyses fill the cloud with estimates, which is why breaks look softer on the map than they are in the water.
Sharp or soft
Some breaks change by a degree or more over a few kilometres, others are gradual. Tap the map and Gannet View measures the nearest break for you: how sharp it is, how far away it lies, and which side is warmer.
Why people look at them
A break separates two water masses and often has a current running along it. People use breaks as one of several things to read on the water. A break on a map is information about the water, not a promise about what is in it.
How old the picture is
Satellite temperature is published a day or more after the pass, and cloud can hide the sea for days. Every layer states its date, and the age of each reading is shown.
Gannet View shows conditions. It does not tell you where fish are.