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Monthly Highlights on the Climate System

'Monthly Highlights on the Climate System' has been issued since March 2007 as a monthly bulletin focusing on the monthly highlights of the monitoring results.

Notice: Products have been upgraded from PDF to HTML format starting from the issue of May 2025 for improved accessibility.

Highlights in November 2025

- In the tropical Pacific, remarkably positive sea surface temperature (SST) anomalies were observed in the western region, while negative anomalies were observed along the equator from the central to eastern regions, indicating a La Niña-like pattern. The NINO.3 index was -0.5°C. In the Indian Ocean, positive SST anomalies were observed in the eastern region and negative anomalies in the western region, resulting in a persistently record-breaking negative phase of the Indian Ocean Dipole. Notably positive SST anomalies were also observed in the subtropical western North Pacific and western South Pacific
- Extremely enhanced convective activity was observed around the Maritime Continent, whereas extremely suppressed convective activity was observed over the Indian Ocean.
- In the upper troposphere, paired anticyclonic circulation anomalies prevailed over the Maritime Continent in both the tropical Northern and Southern Hemispheres, while paired cyclonic circulation anomalies prevailed over the surrounding regions.
- In the lower troposphere, paired cyclonic circulation anomalies were prominently observed from the eastern Indian Ocean to the western Pacific in both the tropical Northern and Southern Hemispheres, while paired anticyclonic circulation anomalies were prominently observed from the central to eastern Pacific. Sea level pressure anomalies were negative from the Maritime Continent to the western Pacific and positive from the central to eastern Pacific, with the Southern Oscillation Index (SOI) recording a value of +1.3.
- In the Northern Hemisphere, the zonal-mean subtropical jet shifted northward relative to its climatological position. The subtropical jet was stronger than normal over the Far East, being displaced northward over East Asia and southward east of Japan. The polar-front jet was stronger than normal between 60°N and 70°N over the Far East.
- In the 500-hPa height field, the polar vortex was centered over central Siberia, accompanied by negative anomalies across northern Eurasia and significantly positive anomalies from northern Canada to Greenland. In the mid-latitude Northern Hemisphere, central Asia was dominated by remarkably positive anomalies. In North America, significantly positive anomalies were observed in the western region, while significantly negative anomalies were observed in the eastern region.
- In the sea level pressure field, positive anomalies were dominant over the Polar Sea, while negative anomalies were observed in the surrounding regions, including northern Eurasia, the northern North Pacific, eastern North America, and the northern North Atlantic. The Aleutian Low was stronger than normal. The Siberian High was weaker than normal over Siberia but extended southward into southern East Asia.
- Okinawa/Amami experienced above-normal temperatures, while other regions experienced near-normal temperatures. The monthly anomaly of the average surface temperature over Japan was +0.25°C. Precipitation amounts were significantly above normal in Okinawa/Amami and above normal in northern Japan, while significantly below normal on the Pacific side of eastern Japan and the Sea of Japan side of western Japan and below normal on the Pacific side of western Japan. Sunshine duration ratios were above normal in all regions of Japan except for Okinawa/Amami and significantly above normal on the Sea of Japan side of eastern Japan.

Climate in Japan (Fig. 1):

- Monthly mean temperatures were above normal in Okinawa/Amami. This was due to the region being covered by warm air.
- The monthly anomaly of the average surface temperature over Japan was +0.25°C. On a longer time scale, the average surface temperatures have risen at a rate of about 1.38°C per century in November.
- Monthly sunshine durations were significantly above normal on the Sea of Japan side of eastern Japan, and above normal on the Sea of Japan side of northern/western Japan and the Pacific side of northern/eastern/western Japan. Monthly precipitation amounts were significantly below normal on the Pacific side of eastern Japan and the Sea of Japan side of western Japan, and below normal on the Pacific side of western Japan. These were due to the regions being frequently covered by high-pressure systems.
- Monthly precipitation amounts were above normal on the Sea of Japan side of northern Japan and the Pacific side of northern Japan due to the frequent passage of low-pressure systems north from Japan.
- In Okinawa/Amami, monthly precipitation amounts were significantly above normal, because the region was affected by Typhoon FUNG-WONG (T2526) and fronts in the first and second ten days of the month.

World Climate:

- The monthly anomaly of the global average surface temperature (i.e., the combined average of the near-surface air temperature over land and the SST) was +0.50°C (3rd warmest for November since 1891) (preliminary value) (Fig. 2). On a longer time scale, global average surface temperatures have risen at a rate of about 0.75°C per century in November (preliminary value).
- Extreme climate events were as follows (Fig. 3).
  - Monthly mean temperatures were extremely high from southwestern Russia to the northwestern Middle East, in northern Canada, from the western USA to Mexico and from New Caledonia to New Zealand.
  - Monthly precipitation amounts were extremely high from Mongolia to northwestern Russia and in and around Thailand.
  - Monthly precipitation amounts were extremely low around the Caspian Sea and in the eastern USA.

Oceanographic Conditions:

- In the equatorial Pacific, negative SST anomalies were observed from the central to eastern parts, and remarkably positive SST anomalies were observed in the western part (Fig. 4). The monthly mean SST anomaly averaged over the NINO.3 region was -0.6°C and the SST deviation from the latest sliding 30-year mean over the region was -0.5°C (Fig. 5).
- In the North Pacific, remarkably positive SST anomalies were observed in the western part of the tropics and in a wide area of the mid-latitudes, while remarkably negative SST anomalies were observed from the Sea of Okhotsk to the western Bering Sea.
- In the South Pacific, remarkably positive SST anomalies were observed in the western part and in the eastern part of the mid-latitudes.
- In the Indian Ocean, remarkably positive SST anomalies were observed in the southeastern part of the tropics, and remarkably negative SST anomalies were observed in the northwestern part of the tropics.
- In the North Atlantic, remarkably positive SST anomalies were observed except in the western part of the mid-latitudes.
- In the South Atlantic, remarkably positive SST anomalies were seen in the western part, and negative SST anomalies were seen in the eastern part in the mid-latitudes.

Tropics:

- Convective activity was enhanced over Southeast Asia, and suppressed from the western to central Indian Ocean, near the dateline of the equatorial Pacific, and the Atlantic (Fig. 6).
- The active phase of equatorial intraseasonal oscillation was seen from the Maritime Continent to the western Pacific, and propagated eastward toward the eastern Pacific in late the month (Fig. 7).
- In the upper troposphere, anti-cyclonic circulation anomalies straddling the equator were seen over the Maritime Continent, and cyclonic circulation anomalies straddling the equator were seen from Africa to the western Indian Ocean, and from the central Pacific to South America (Fig. 8).
- In the lower troposphere, cyclonic circulation anomalies straddling the equator were seen from the eastern Indian Ocean to Indonesia, and anti-cyclonic circulation anomalies were seen over the central Pacific (Fig. 9).
- In the sea level pressure field in tropics, negative anomalies were seen around Southeast Asia, and positive anomalies were seen from the central Pacific to the Indian Ocean through the Atlantic. In the equator, westerly and easterly wind anomalies were seen over the eastern Indian Ocean and from the western to central Pacific, respectively. The Southern Oscillation Index value was +1.3 (Fig. 5).

Extratropics:

- In the 500-hPa height field (Fig. 10), the polar vortex was centered in Central Siberia, accompanied by negative anomalies in northern Eurasia and positive anomalies from northeastern Canada to Greenland. In the Northern Hemisphere mid-latitudes, significant positive anomalies were seen in Central Asia, and significant positive and negative anomalies were seen in western and eastern North America, respectively.
- The jet stream shifted slightly northward compared to the climatological normal and was stronger than normal around Japan. The polar-front jet was strong between 60°N and 70°N in Eurasia (Fig. 11).
- In the sea level pressure field (Fig. 12), positive anomalies were seen in Arctic Ocean, and negative anomalies were seen in northern Eurasia, the northern North Pacific and from northern North America to the northern North Atlantic, with the Aleutian Low being stronger than normal. Positive anomalies were seen in southern East Asia, with the Siberian High extending further south than normal.
- In the 850-hPa temperature field (Fig. 13), positive and negative anomalies were seen in the western and eastern Hemisphere sides in the high-latitudes, respectively. In the Northern Hemisphere mid-latitudes, positive anomalies were seen over Eurasia, with significant positive anomalies in Central Siberia. Positive and negative anomalies were seen in western and eastern North America, respectively.

Zonal mean:

- In the zonal mean zonal wind in the troposphere, the jet stream in both hemispheres shifted slightly northward compared to the climatological normal.
- The zonal mean temperatures in the troposphere were above normal, except over the polar regions of the Northern Hemisphere and near 50°S in the Southern Hemisphere. The zonal mean temperatures in the stratosphere were below normal south of 60°N and above normal north of 60°N.

Supplemental information

- Climate Anomaly Table over Japan
- Extratropics in the Southern Hemisphere
- Snow in the Northern Hemisphere
- Arctic sea ice (link to the National Snow and Ice Data Center)

Fig.1 Monthly climate anomaly/ratio over Japan (November 2025) Top: temperature anomalies (degree C) Middle: precipitation ratio (%) Bottom: sunshine duration ratio (%) The base period for the normal is 1991-2020.

Fig.10 Monthly mean 500-hPa height and anomaly in the Northern Hemisphere (November 2025) The contours show 500-hPa height at intervals of 60 m. The shading indicates its anomalies. The base period for the normal is 1991-2020.	Fig.11 Monthly mean 200-hPa wind speed and vectors in the Northern Hemisphere (November 2025) The black lines show wind speed at intervals of 15 m/s. The brown lines show its normal at intervals of 30 m/s. The base period for the normal is 1991-2020.
Fig.12 Monthly mean sea level pressure and anomaly in the Northern Hemisphere (November 2025) The contours show sea level pressure at intervals of 4 hPa. The shading indicates its anomalies. The base period for the normal is 1991-2020.	Fig.13 Monthly mean 850-hPa temperature and anomaly in the Northern Hemisphere (November 2025) The contours show 850-hPa temperature at intervals of 4 degree C. The shading indicates its anomalies. The base period for the normal is 1991-2020.

Back Number

The descriptions from May-2011 to April-2021 issue are based on the former climatological normal (1981-2010 average).
In the descriptions until April-2011 issue, 1979-2004 average is used as climatological normal unless otherwise stated.
The descriptions until January-2014 issue are based on the JRA-25/JCDAS datasets.
The descriptions from February-2014 to April-2023 issue are based on the JRA-55 reanalysis.

Figures and Tables

Notice: Products based on JRA-3Q were updated to those with improved quality in terms of tropical cyclone analysis. OLR-related products from January 1991 are based on NOAA CPC Blended OLR (CBO).

Notice: Figures of 'Atmospheric Circulation', 'Time Cross Section', and 'Indices' have been revised with improved quality data regarding tropical cyclone analysis. (18 June 2024)

Notice: Depending on the availability of NOAA CPC Blended OLR (CBO) data, updates may be delayed or figures may be filled with gray indicating data missing.

• Explanation on the Products for Climate System Monitoring
• 5-day Mean Figures
• 10-day Mean Figures
• Monthly Mean Figures
• 3-month Mean Figures
• Time Cross Sections
• Indices
• Oceanic Figures and Tables