<\/p>\n
Monitoring informs action<\/p>\n
El Ni\u00f1o and La Ni\u00f1a are opposite phases of the El Ni\u00f1o\u2013Southern Oscillation (ENSO); one of the most powerful naturally occurring climate patterns on Earth.<\/p>\n
El Ni\u00f1o is characterized by a warming of ocean surface temperatures in the central and eastern Equatorial Pacific. It typically occurs every two to seven years and lasts around nine to twelve months.<\/p>\n
It generally begins developing between March and June and reaches its peak intensity between November and February, with impacts on global temperatures typically being most pronounced in the second year after development. \u00a0<\/p>\n
The effects of each El Ni\u00f1o\/La Ni\u00f1a event vary depending on the intensity, duration, time of year when it develops, and also how it interacts with other climate variability modes (such as the Indian Ocean Dipole). Not all regions of the world are affected, and even within a region, impacts can be different. Even when ENSO is neutral, extreme weather can still occur. \u00a0<\/p>\n
The strength of an ENSO event is highly significant \u2013 whether it is classed as weak, moderate, strong or very strong. Even a moderate El Ni\u00f1o makes some weather and climate extremes more likely.<\/p>\n
WMO does not use the term \u201csuper El Ni\u00f1o\u201d because it is not part of standardized operational classifications.<\/p>\n
There is no evidence that climate change increases the frequency or intensity of El Nino events. But it can amplify associated impacts because a warmer ocean and atmosphere increases the availability of energy and moisture for extreme weather events such as \u00a0heatwaves and heavy rainfall.<\/p>\n
Typical impacts<\/p>\n
Each El Ni\u00f1o event is unique in terms of its evolution, spatial pattern and impacts. \u00a0<\/p>\n
However, it is typically associated with increased rainfall in parts of southern South America, the southern United States, parts of the Horn of Africa and central Asia, and drier conditions over Central America, northern South America, the Caribbean, Australia, Indonesia, and parts of southern Asia.<\/p>\n
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During the Boreal summer, El Ni\u00f1o\u2019s warm water can fuel hurricanes in the central\/eastern Pacific Ocean, while it hinders hurricane formation in the Atlantic Basin. Thus, the US National Oceanic and Atmospheric Administration (NOAA) is forecasting a below-normal hurricane season for the Atlantic basin this year<\/a>.<\/p>\n National Meteorological and Hydrological Services and WMO Regional Climate Centres and Regional Climate Outlook Forums issue regularly updated information to inform national and regional decision-making. WMO is also providing regular briefings to humanitarian agencies via the WMO Coordination Mechanism.<\/p>\n For example, the Greater Horn of Africa Climate Outlook Forum (GHACOF) predicts a high likelihood of below-normal rainfall across much of the northern Greater Horn of Africa<\/a> during the critical June\u2013September rainy season.\u00a0<\/p>\n Similarly, South Asia is expected to receive below average monsoon rainfall, according to the South Asian Climate Outlook Forum<\/a>. \u00a0<\/p>\n The Central America region expects drier and warmer conditions according to the Central America Climate Outlook Forum<\/a>.<\/p>\n Global Seasonal Climate Update<\/p>\n