[El Niño / La Niña]
In June 2025, the sea surface temperature (SST) for the NINO.3 region was near normal with a deviation of -0.2°C (Fig.3 and Table). The five-month running mean value of the NINO.3 SST deviation for April 2025 was +0.1°C. SSTs in the equatorial Pacific were above normal in the western part and below normal in the eastern part (Fig.4 and Fig.6). Subsurface water temperatures in the equatorial Pacific were above normal in the western and central parts, while they were below normal in the eastern part (Fig.5 and Fig.7). In the atmosphere, easterly winds in the lower troposphere (i.e., trade winds) over the equatorial Pacific were stronger than normal in the central part, but were near normal in the eastern part. Convective activity was enhanced near the Maritime Continent but was near normal near the dateline over the equatorial Pacific (Fig.8, Fig.9 and Fig.10). These oceanic and atmospheric conditions indicate that ENSO-neutral conditions persisted in June.
JMA's seasonal ensemble prediction system predicts that NINO.3 SST will decrease due to the persistence of stronger-than-normal easterly winds over the equatorial Pacific. However, this prediction may be influenced by predicted above-normal SSTs in the eastern part of the tropical Indian Ocean, for which prediction accuracy is low. In conclusion, it is more likely (60%) that ENSO-neutral conditions will persist to boreal autumn than La Niña conditions will develop (40%).
[Western Pacific and Indian Ocean]
The area-averaged SST in the tropical western Pacific (NINO.WEST) region in June was near normal (Fig.3). The index is likely to be above or near normal until boreal autumn (Fig.12).
The area-averaged SST in the tropical Indian Ocean (IOBW) region was near normal in June (Fig.3). The index is likely to be below or near normal until boreal autumn (Fig.13).
The seasonal climate outlook for Japan is available here .
In June 2025, the sea surface temperature (SST) for the NINO.3 region was near normal with a deviation of -0.2°C (Fig.3 and Table). The five-month running mean value of the NINO.3 SST deviation for April 2025 was +0.1°C. SSTs in the equatorial Pacific were above normal in the western part and below normal in the eastern part (Fig.4 and Fig.6). Subsurface water temperatures in the equatorial Pacific were above normal in the western and central parts, while they were below normal in the eastern part (Fig.5 and Fig.7). In the atmosphere, easterly winds in the lower troposphere (i.e., trade winds) over the equatorial Pacific were stronger than normal in the central part, but were near normal in the eastern part. Convective activity was enhanced near the Maritime Continent but was near normal near the dateline over the equatorial Pacific (Fig.8, Fig.9 and Fig.10). These oceanic and atmospheric conditions indicate that ENSO-neutral conditions persisted in June.
JMA's seasonal ensemble prediction system predicts that NINO.3 SST will decrease due to the persistence of stronger-than-normal easterly winds over the equatorial Pacific. However, this prediction may be influenced by predicted above-normal SSTs in the eastern part of the tropical Indian Ocean, for which prediction accuracy is low. In conclusion, it is more likely (60%) that ENSO-neutral conditions will persist to boreal autumn than La Niña conditions will develop (40%).
[Western Pacific and Indian Ocean]
The area-averaged SST in the tropical western Pacific (NINO.WEST) region in June was near normal (Fig.3). The index is likely to be above or near normal until boreal autumn (Fig.12).
The area-averaged SST in the tropical Indian Ocean (IOBW) region was near normal in June (Fig.3). The index is likely to be below or near normal until boreal autumn (Fig.13).
The seasonal climate outlook for Japan is available here .
另外还要考虑地球自转速度/每日长度，像60-70年代LOD很长，而近几年就基本上是有纪录以来最短。LOD除了影响赤道附近信风/西风的活动外，还可能通过QBO的角动量下传影响TEJ的强度，从而影响西太TC的
