When we look at water angles are important. Looking across the water, at shallow angles, we see mostly reflections – the colour of the water is determined mainly by the colour of the sky.
If we look down, at steep angles, we can see through the water.
There is a physical way of remembering and testing this yourself:
Stretch out your arm and make a fist.
Two fists below the horizon – above that you will see reflections, below it you can see underwater.
For more water-reading tips, please see the book, How to Read Water: