El Nino Watch
The cool phase of ENSO: the central and eastern tropical Pacific is cooler than normal and the trade winds are stronger. For Thailand it tends to mean more rain.
El Nino basics
La Nina is the opposite of El Nino. The central and eastern tropical Pacific is cooler than normal, the trade winds blow harder, and the warm water and rain clouds are pushed even further west, over Indonesia and Southeast Asia.
La Nina often follows a strong El Nino, but not always. It typically lasts 1 to 3 years, longer than a typical El Nino (9 to 12 months).
La Nina conditions: one-month relative Nino 3.4 anomaly of -0.5 °C or less, with the 3-month RONI expected to stay below -0.5 °C, plus an atmospheric response.
La Nina years tend to be wetter than normal in Thailand. Samui is now in an El Nino, so La Nina matters mostly as the possible next phase in 2027-2028.