From December to April any outer planet in nino 5 will be moving in arc in a retrograde motion that is from east to west. This is coincident with the yearly warming period in nino 5.
Any outer planet in nino 5 will be moving retrograde from January to May. This is coincident with the yearly buildup of warm water in nino 4, while the cooling of nino 5 is coincident with the direct motion of any planet in April. This means that as a planet in nino 5 starts to go direct in April that sector cools off and the sector further east starts warming. This is the usual case since nino 4 would be under the influence of a retrograde planet while nino 5 would be under the influence of a direct moving planet. The border between nino 5 and nino 4,that is the area between the two planets is in effect, “squeezed” by the opposing motions of the two planets.
Any outer planet in central nino 3.4 at the dateline will be moving retrograde from March to July. This is coincident with the important warming of the dateline waters in July. An outer planet in this position is a strong indicator of the potential for the emergence of el nino like conditions in the eastern Pacific later in the year. This is because it will go direct (west to east) in July just at the time and the place that an impulse is needed to encourage the warmth to flow to the east from the dateline.
Any outer planet in nino 3 will go retrograde from June to October. This is coincident with the canonical el nino. Finally, any outer planet in nino 1+2 will go retrograde in July and direct in December. This is coincident with the arrival of warm water on the west coast of Peru at Christmas. This placement is coincident with the canonical el nino.
The whole phenomenon.
Read the Case Study for the 1982-83 El Nino.