A lot of attention has been given to the consequences of the latest strong El Niño event. People often talk about meteorological phenomena as El Niño (or La Niña) conditions, but what are these, and how do we come about our notions of what is a ’typical’ El Niño event? How consistent do we expect the effects of this phenomena to be, especially when these ’signature effects’ occur thousands of kilometers away from the Pacific Ocean? Often understanding about the typical effects of large scale climate variations are derived from _composites_. This is a common statistical method where elements are classified into groups based on some external consideration, and then the properties of each group is expressed by the average of all the elements it contains. This can be a very efficient way to visualize large data sets, but it can also imply more consistency within groups than is actually the case. This post goes over some of mechanics of creating composites, and ways to explore to what degree they can be taken at ’face value’.