Santiago's rainfall is highly variable and heavily influenced by the El Niño Southern Oscillation cycle, with rainy years coinciding with El Niño events and dry years with La Niña events. The wettest year since records began in 1866 was 1900 with  – part of a "pluvial" from 1898 to 1905 that saw an average of  over eight years incorporating the second wettest year in 1899 with  – and the driest 1924 with . Typically there are lengthy dry spells even in the rainiest of winters, intercepted with similarly lengthy periods of heavy rainfall. For instance, in 1987, the fourth wettest year on record with , there was only  in the 36 days between 3 June and 8 July, followed by  in the 38 days between 9 July and 15 August.