The El Niño-Southern Oscillation, also known as ENSO, is a phenomenon that occurs in the tropical Pacific Ocean. When average water temperatures are above average, it dictates that an El Niño is present; when temperatures are below average, La Niña is present.
These phenomena not only bring cooler or warmer-than-average temperatures but also create shifts in the wind shear around the globe and changes in the position of the jet stream, which bring significant changes in weather patterns while they are present.
La Niña events typically occur every 3 to 5 years, but the interval between events can vary from 2 to 7 years.
El Niño or La Niña may be present at any time of the year, but depending on the season, some regions may be more severely affected by even worse extreme weather conditions.
This fall, La Niña appears to be slowly developing. Scientists said that there is a 71 percent chance of La Niña developing and persisting through December.
However, between December and February, during the winter months, there is a 54 percent chance of this happening, and long-term models continue to indicate a decrease through the spring of 2026. This shift in the pattern is expected to last at least through February 2026.
How does La Niña affect the fall and winter?
When La Niña is present in the cooler months, it typically displaces the jet stream, causing it to shift more northward; this tends to bring drier and warmer-than-normal conditions during its duration. The jet stream´s northward displacement keeps storms moving across northern latitudes and less frequent, more south. Fewer storms moving across the South means the weather pattern will stay drier, and with fewer storms that bring clouds, temperatures tend to stay warmer. Water temperatures also tend to stay warmer than average across the Gulf and eastern Atlantic.
What does it mean for Florida?
When a La Niña is present in winter, the season tends to stay warmer and drier than usual. This pattern was present during the winter of 2016-2017. Late January and February are the coolest months, and 2017 started relatively warm. Many Floridians might remember that the holidays were warmer than usual. There were some slight variations, and cold fronts pushed through, but they were short-lived.
For example, Central Florida's coldest temperature in January 2017 was 36°F. In February 2017, the highest maximum temperature reached 87°F, and the lowest recorded temperature was 43°F. For context, the average high temperature in Orlando for February is 72.9°F, and the average low is 52.1°F. The average high temperature in February 2017 was 80.9°F, and the average low was 56°F. That's 8 degrees above average for the high and 3.9 degrees above average for the low.
Having a La Niña event does not mean we will not experience cold snaps. There will be storms and some cold fronts, but they will be less frequent and perhaps less intense. Once the season is over, we will look back and notice that the overall trend was warmer than average.
How does this affect wildfires?
Wildfire season in Florida lasts year-round, with the peak typically occurring between April and June. A drier winter may signal an increase in wildfires in the spring and early summer. La Niña brings drier conditions that coincide with Florida's dry season. This could exacerbate any drought that develops in the spring and serve as fuel to any wildfires that might spark after winter.
This summer season was particularly challenging due to the drought, with many populated areas in the southeast experiencing drought conditions for most of the rainy season. September brought much-needed rain across the South, but abnormally dry conditions have resurfaced in the North and Panhandle, and the dry season is about to begin.
Copyright 2025 Storm Center
