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.
The sea surface temperatures (SSTs) over the tropical Pacific have weakened to ENSO-neutral SST anomaly levels in the central to the western Pacific and continued to cool in the eastern Pacific to the far eastern Pacific Ocean. However, near to above average SST anomalies are still evident in the western Pacific to the Maritime Continent.
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 IOD was still observed during the month but SST anomalies over the western equatorial Indian Ocean are slightly below than the eastern equatorial Indian Ocean.