A. Niño Regions

Niño sea surface temperature (SST) Indices are based on the average of SST anomalies across the given regions: Niño 1+2 (0-10S, 90W-80W), Niño 3 (5N-5S, 150W-90W), Niño 3.4 (5N-5S, 170W-120W) and Niño 4 (5N-5S, 160E-150W). These indices are used to monitor the conditions in the Tropical Pacific for the occurrence of El Niño or La Niña.

Near average sea surface temperature anomalies (SSTAs) were present over the tropical Pacific during the month. Positive anomalies were evident from the central to the western Pacific while negative anomalies (cooling) in the eastern Pacific to the far eastern Pacific Ocean persisted. However, near to above average SSTs were observed over the western Pacific to the Maritime Continent.

B. Indian Ocean Dipole (IOD)

The Indian Ocean Dipole mode Index (DMI) is defined as the difference between the SST anomalies (ºC) of Western (10ºS-10ºN & 50ºE-70ºE) and Eastern (10ºS-0ºN & 90ºE-110ºE) Equatorial Indian Ocean regions (WEST-EAST). The DMI values represent the intensity of the Indian Ocean Dipole (IOD); DMI values above +0.4 °C is referred as the positive IOD, DMI values below −0.4 °C is referred as the negative IOD and DMI values between +0.4 °C and -0.4 °C is referred as the neutral IOD.

Neutral values of IOD were still observed during the month but SST anomalies over the western equatorial Indian Ocean were slightly cooler than the eastern equatorial Indian Ocean.