ENSO Composites

El Niño Precipitation Composites

The plots below, which are called 'composites', show the average effect of La Niña on precipitation. Each dot on the map represents a data station. The color of each dot is determined by the average of the precipitations over several La Niña events. A brown dot means below-average precipitation, a green dot means above-average precipitation, and a grey dot means near-average precipitation. White areas (without any dots) have few or no data stations. There is a detailed explanation of how the plots were made at the bottom of the page.

January to March

April to June

July to Spetember

October to December

Detailed Explanation

• For each season (Jan to Mar, etc.), we defined La Niña years by taking the coldest 20% of Nino3 years for that season from 1900 to 1990.
• For each season and each location we calculated the median rainfall over all La Niña years.
• We defined precipitation terciles for each location based on the 1900-19900 period.
• We colored each dot according to which tercile the median precipitation during La Niña years fell in.