Ontario residents may be in for significant weather changes over the coming months as El Niño has officially returned and is expected to strengthen, potentially developing into one of the strongest events in recent decades. Meteorologists say the evolving climate pattern could bring a warmer-than-normal winter, changing precipitation patterns and increasing concerns about drought, wildfires and severe weather.
The U.S. National Oceanic and Atmospheric Administration (NOAA) officially declared the arrival of El Niño earlier this month after sea surface temperatures in the central and eastern Pacific Ocean climbed more than one degree Celsius above normal. Canadian meteorologists say the warming trend is expected to continue through the remainder of the year, with the greatest impacts likely to be felt during the fall and winter seasons.
Geoff Coulson, Warning Preparedness Meteorologist with Environment and Climate Change Canada, said the current El Niño is still in its early stages but has the potential to develop into a “super El Niño” later this year. He noted that if the event continues strengthening, Canadians could experience a much milder winter similar to the powerful El Niño of 2015-16.
Scientists have observed unusually warm ocean temperatures this summer. June 2026 recorded the highest tropical Pacific Ocean temperatures ever measured, while global sea surface temperatures across the Pacific, Atlantic and Mediterranean also reached record highs. These warming oceans are considered strong indicators that El Niño conditions are becoming firmly established.
Under normal conditions, trade winds push warm surface waters across the Pacific Ocean, allowing colder, nutrient-rich waters to rise from below. During El Niño, however, those winds weaken, causing warm water to spread across the eastern Pacific. This shift alters atmospheric circulation and influences weather patterns across much of the world.
For Canada, El Niño typically shifts the Pacific jet stream southward, resulting in warmer and generally drier conditions across much of the country, while the southern United States often experiences wetter weather. Although El Niño does not guarantee a hot summer in Ontario, its greatest influence is usually felt during the colder months by producing milder winters and reduced snowfall.
Canada has just emerged from two consecutive La Niña winters, which contributed to heavy snowfall across many regions during the past two years. With La Niña now fading, meteorologists expect El Niño to dominate weather patterns well into 2027.
Current measurements indicate Pacific Ocean temperatures are approximately 1.2 degrees Celsius above normal, already surpassing the threshold required to classify an El Niño event. Scientists say a super El Niño occurs when temperatures rise two degrees Celsius or more above average. Some forecasts suggest the affected region of the Pacific could warm by as much as 3.5 degrees Celsius later this year, raising the possibility of one of the strongest El Niño events on record.
NOAA forecasts indicate an 81 per cent probability that a very strong El Niño will develop during the October to December period and expects the phenomenon to persist through at least the early spring of 2027.
The changing weather pattern could have far-reaching consequences beyond warmer temperatures. Experts warn that prolonged warmth and reduced snowfall may increase the risk of drought conditions and contribute to a more severe wildfire season next year. Northern Ontario has already experienced extensive wildfire activity this summer, with hundreds of fires burning across the region, while smoke has periodically affected communities across southern Ontario and parts of the United States.
Meteorologists are also closely monitoring the potential influence of El Niño on tropical storm and hurricane activity. Although forecasting remains challenging, atmospheric conditions may become more favourable for tropical cyclone development in parts of the Pacific and Atlantic later this year.
The effects of El Niño extend beyond weather. Warmer ocean temperatures reduce the upwelling of nutrient-rich waters that support marine ecosystems, leading to lower phytoplankton production and affecting fish populations and the species that depend on them. Warmer waters may also allow tropical fish species to migrate into regions that are normally too cold for them.
While forecasters caution that individual weather events cannot be attributed solely to El Niño, the evolving climate pattern is expected to play a major role in shaping Canada’s weather over the coming months. Ontario residents are encouraged to stay informed through official weather forecasts as meteorologists continue monitoring what could become one of the strongest El Niño events in decades.