Effects of the El Niño–Southern Oscillation in Australia is present across most of Australia, particularly the north and the east, and is one of the main climate drivers of the country. Associated with seasonal abnormality in many areas in the world, Australia is one of the continents most affected and experiences extensive droughts alongside considerable wet periods that cause major floods. There exist three phases — El Niño, La Niña, and Neutral, which help to account for the different states of ENSO. Since 1900, there have been 27 El Niño and 18 La Niña events in Australia. The events usually last for 9 to 12 months, but some can persist for two years, though the ENSO cycle generally operates over a time period from one to eight years.