HisTogRams

These histogram show the actual exposure used at capture with combined brightness values shown in the top graph and then the red, green and blue channels below. The latter will tell you if any one colour is skewing an exposure. In this instance, they’re all pretty similar and the exposure is pretty accurate overall. The spikes towards the brighter end of the histogram relate to the lighter areas of sky and so you might decide to underexpose a little to ensure more detail is retained in the brightest highlights.