El Niño: characterized by a positive ONI greater than or equal to +0.5ºC. La Niña: characterized by a negative ONI less than or equal to -0.5ºC. By historical standards, to be classified as a full-fledged El Niño or La Niña episode, El Niño: characterized by a positive ONI greater than or equal to +0.5ºC. La Niña: characterized by a negative ONI less than or equal to -0.5ºC. By historical standards, to be classified as a full-fledged El Niño or La Niña episode, these thresholds must be exceeded for a period of at least 5 consecutive overlapping 3-month seasons. These thresholds have exceeded for a period of only 4 consecutive overlapping 3-month seasons. The ONI Index being SON 0.5, OND 0.7, NDJ 0.7 & last DJF 0.6 . If JFM =>0.5 then an El Nino can be declared, so we have one more month before an El Nino can be confirmed or not confirmed.