El Niño, La Niña, and the 2025 Forecast: what farmers can expect this season

Every farmer wishes they had a crystal ball to predict what Manitoba’s growing season will bring. Will it be another dry year, or will mud-slicked fields make seeding a challenge? While no one can see the future, there is one global weather phenomenon that offers valuable clues for long-range forecasting – and it’s shaping predictions for the 2025 crop season.

Scott Kehler, meteorologist, president and chief scientist of Weatherlogics, has spent years analyzing weather patterns and developing forecasting tools to help farmers and industry professionals prepare for whatever Mother Nature has in store.

With a bachelor’s and master’s degree in meteorology from the University of Manitoba, Kehler specializes in weather research, improving prediction methods, and analyzing past climate events. Despite his focus on research, he remains passionate about day-to-day forecasting, particularly for high-impact weather events.

During his presentation at St Jean Farm Days in January, Kehler shed light on two significant climate patterns – El Niño and La Niña – and how they consistently shape winter weather trends across North America.

Understanding El Niño and La Niña

“These events are driven by shifts in sea surface temperatures in the central and eastern Pacific Ocean along the equator,” Kehler explained. “El Niño is associated with above-average ocean temperatures, while La Niña brings cooler-than-normal waters. These changes influence global weather patterns, including the likelihood of extreme weather events.”

El Niño and La Niña have been occurring for at least 10,000 years. Some historians suggest that El Niño may have even contributed to poor crop yields in Europe between 1789 and 1793, potentially fueling the French Revolution. These events occur on an irregular cycle, typically every two to seven years, and can last anywhere from nine to 12 months, sometimes longer.

Since 1900, there have been about 30 El Niño events, with the most recent in 2023-24 and the strongest recorded in 2015-16. Likewise, there have been about 30 La Niña events since 1900, with the most recent occurring from 2020-23 and the strongest on record in 1973-74.

Why do we care about Pacific Ocean temperatures?

“The Pacific Ocean makes up such a massive part of the Earth’s surface – about five times the area of Canada,” Kehler explained. “These temperatures affect global weather patterns. They influence the jet stream due to the difference in temperature between areas to our south and areas to our north.”

The jet stream is a key driver of North American weather. During El Niño, temperature differences tend to be less pronounced, weakening the jet stream and making it more difficult for cold air masses to move south. Conversely, La Niña strengthens the jet stream, increasing temperature differences and allowing Arctic air to push further south, often resulting in colder and snowier conditions.

“Although these patterns don’t guarantee extreme weather, they increase the probability of certain conditions developing,” Kehler said. “If you look at the past decade, the warmest and coolest years have almost always coincided with an El Niño or La Niña event.”

But there is a third option: neutral.

“The stronger the El Niño or La Niña, the greater its impact on our weather,” Kehler noted. “So far, we’ve been kind of in the middle, so we don’t really see any weather extremes over long periods of time. We’ll see a lot of ups and downs throughout the winter.”

2024 weather trends: a year of extremes

Last year, precipitation was highly variable across the Prairies. Manitoba saw the wettest areas along the escarpment due to heavy late May rains, but conditions turned drier than average in July and August. By November, unusual rainfall in the Red River Valley resulted in the rainiest November on record for Winnipeg.

According to a fall 2024 survey, soil moisture was variable across the region. “There was a lot of concern for how dry it was, especially in South Central and Southwestern Manitoba. But we actually recovered fairly well in the spring, which got the season off to a much better start,” Kehler said.

What’s in Store for 2025?

As of December 2024, the Pacific Ocean remained in neutral conditions, meaning neither El Niño nor La Niña was in effect. “This means the forecast is far more uncertain than usual,” Kehler admitted. “When we don’t have a strong El Niño or La Niña, that takes away one of the factors we can point to when making our long-range forecast.”

However, by May 2025, El Niño is expected to return and strengthen through the fall. “We’re quite uncertain at this point about the weather next winter,” he added.

For Manitoba farmers, here’s what to expect in 2025:

• Temperature Outlook: Overall, cooler-than-normal summer conditions, particularly in the spring. “It looks like this winter might be a little slow to leave, and with La Niña in place, there’s a chance we’ll see more snow. The snowpack could keep things a little cooler into spring.” Summer temperatures will be normal to slightly below normal.

• Precipitation Outlook: Wetter-than-normal conditions are expected, with a cooler start to spring followed by normal levels of rain and snow. As summer progresses, precipitation is projected to be above normal.

• Thunderstorm Activity: In 2024, Manitoba saw an active thunderstorm season with few severe events. “2025 will likely be similar,” Kehler predicted.

Preparing for uncertainty

Long-range forecasting remains a challenge, but trends in ocean temperatures, atmospheric oscillations, and solar cycles offer valuable insights. “Many farmers receive day-to-day forecasts, but long-range forecasts use entirely different methods,” Kehler emphasized. “Water temperatures change very slowly. It takes a lot of energy to alter ocean temperatures, so we rely on these indicators for longer-term predictions.”

While the 2025 growing season remains uncertain, the expected transition from neutral conditions to El Niño suggests a wetter-than-normal summer with cooler-than-normal temperatures. For farmers, this means careful planning and flexibility will be key.

“As always, weather remains one of the most unpredictable factors in agriculture, but by understanding patterns like El Niño and La Niña, farmers can better prepare for what lies ahead.”