Globe image courtesy of NOAA. Stock images courtesy of Canva.
Welcome to The Weather Network's hub for all information on El Niño and La Niña
This page contains information on El Niño, La Niña, and how these important patterns influence your weather here in Canada.
Browse our video and news galleries and feel free to share this information as you prepare for the seasons ahead.
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The El Niño-Southern Oscillation (ENSO) plays a significant role in Canada’s winters and summers, featuring prominently in seasonal forecasts across the country.
El Niño and La Niña are patterns of warmer- and cooler-than-seasonal water temperatures in the eastern Pacific Ocean around the equator. These anomalies have a major influence on weather patterns around the world, including here in Canada.
El Niño and La Niña are patterns of warmer- and cooler-than-seasonal water temperatures in the eastern Pacific Ocean around the equator. These anomalies have a major influence on weather patterns around the world, including here in Canada.
Diagram image courtesy of NOAA.
Under normal conditions, prevailing winds blow from east to west across the equatorial Pacific Ocean. These winds usually push warmer surface water toward Australia, helping frigid water from deep below to rise to the surface off South America’s western shores.
Forecasters monitor water temperatures in a specific region of the eastern Pacific Ocean for changes that could influence global weather patterns.
A water temperature anomaly in this region of at least 0.5°C above-seasonal for about half a year qualifies as an El Niño, while a similar stretch of water temperatures that are 0.5°C or more below seasonal is a La Niña.
Stronger temperature anomalies make for stronger El Niño and La Niña events, which can have greater and more far-reaching effects around the world.
A water temperature anomaly in this region of at least 0.5°C above-seasonal for about half a year qualifies as an El Niño, while a similar stretch of water temperatures that are 0.5°C or more below seasonal is a La Niña.
Stronger temperature anomalies make for stronger El Niño and La Niña events, which can have greater and more far-reaching effects around the world.
EL NIÑO
An El Niño sees this wind pattern break down or even reverse, allowing unusually warm water to pool up off the coast of South America. Named ‘the little boy’ by fishermen who noticed the pattern around Christmastime, we feel El Niño’s greatest effects during the winter months.
A typical El Niño sets up a winter pattern that often brings above-seasonal temperatures to much of Canada—especially the western half of the country.
A typical El Niño sets up a winter pattern that often brings above-seasonal temperatures to much of Canada—especially the western half of the country.
Patterns influenced by El Niño can create a favourable track for East Coast storms, with snowbirds potentially facing wet and stormy conditions in Florida.
The summertime effects of El Niño are somewhat muted across Canada. However, the warm waters of an El Niño can increase wind shear flowing east over the neighbouring Atlantic Ocean. This wind shear can disrupt tropical disturbances before they have a chance to develop, which can lead to a below-average Atlantic hurricane season.
The strongest El Niño event on record occurred during the winter of 2015-2016, when water temperatures were more than 2.5°C warmer than normal for several consecutive months.
The summertime effects of El Niño are somewhat muted across Canada. However, the warm waters of an El Niño can increase wind shear flowing east over the neighbouring Atlantic Ocean. This wind shear can disrupt tropical disturbances before they have a chance to develop, which can lead to a below-average Atlantic hurricane season.
The strongest El Niño event on record occurred during the winter of 2015-2016, when water temperatures were more than 2.5°C warmer than normal for several consecutive months.
LA NIÑA
La Niña, which is Spanish for ‘the little girl,’ is the direct opposite of El Niño.
Prevailing winds over the eastern Pacific sometimes strengthen and push more warm water toward Australia, a process that enhances the upwelling of frigid water off the western coast of South America.
The persistently cold water temperatures of a La Niña event can have noticeable effects on Canada’s winter weather. Below-seasonal temperatures and wetter-than-usual conditions are common of La Niña winters in Western Canada, while an active storm track can lead to volatile swings for folks across the Great Lakes and the Atlantic provinces.
The persistently cold water temperatures of a La Niña event can have noticeable effects on Canada’s winter weather. Below-seasonal temperatures and wetter-than-usual conditions are common of La Niña winters in Western Canada, while an active storm track can lead to volatile swings for folks across the Great Lakes and the Atlantic provinces.
Summer weather during a La Niña is often dominated by an active Atlantic hurricane season.
A reduction in wind shear makes conditions more favourable in the Gulf of Mexico, Caribbean Sea, and open Atlantic Ocean for tropical disturbances to develop and thrive. Some of the most active Atlantic hurricane seasons on record occurred during strong La Niña events.
La Niña events tend to be weaker than their warmer counterparts, with the strongest La Niña registering average water temperatures -2.0°C below seasonal during the winter of 1973-1974.
A reduction in wind shear makes conditions more favourable in the Gulf of Mexico, Caribbean Sea, and open Atlantic Ocean for tropical disturbances to develop and thrive. Some of the most active Atlantic hurricane seasons on record occurred during strong La Niña events.
La Niña events tend to be weaker than their warmer counterparts, with the strongest La Niña registering average water temperatures -2.0°C below seasonal during the winter of 1973-1974.
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