https://www.worldclimateservice.com/2021/05/14/enso-spring-barrier/
However, as winter ends and spring begins, the models quickly recover their long-lead skill, and as early as March the spring barrier is greatly reduced. In practical terms, we should distrust any forecast issued in winter or earlier that looks beyond spring into summer or beyond. But the forecasts are considerably more accurate by March, and each month after that improves the skill incrementally up to the autumn peak in long-lead skill.
Wachten tot maart.