La Nina 2025 To 2026 Forecast. La niña begins when pacific trade winds strengthen, pushing warm surface waters westward and allowing cooler water to rise in the eastern pacific. That possibility remains but is considerably weaker.

The latest data predicts a shift from the current el niño phase to la niña conditions, with a more than 50% chance of la niña developing by december 2024 through. Forecast uncertainty for what would now become an unseasonably late la niña development.