Explaining Terciles a brief illustration

Imagine two places that are near each other and receive amounts of rainfall that are roughly correlated, even though in any given year Place 2 is usually wetter than Place 1.

Below Normal Near Normal Above Normal

mm of Rain

The wettest ten years from the data fall in the above normal tercile. mm of Rain

The wettest ten years from the data fall in the above normal tercile. mm of Rain The driest ten years from the data fall in the below normal tercile.

The wettest ten years from the data fall in the above normal tercile. The middle ten years from the data fall in the near normal tercile. mm of Rain The driest ten years from the data fall in the below normal tercile.

For each place we can see a range of rainfall amounts corresponding to each tercile. mm of Rain

For each place we can see a range of rainfall amounts corresponding to each tercile. mm of Rain

For each place we can see a range of rainfall amounts corresponding to each tercile. mm of Rain

For each place we can see a range of rainfall amounts corresponding to each tercile. mm of Rain 35 percent chance of receiving >445mm in place 1, and >470mm in place 2. 40 percent chance of receiving 346-445mm in place 1, and 368-469mm in place 2. 25 percent chance of receiving <346mm in place 1, and <368 in place 2.