Monthly Highlights on the Climate System

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

Notice: From 19 May 2021 onward, the products in this page are based on the new climatological normal (1991-2020 average) unless otherwise stated.

Highlights in December 2022

- Atmospheric and oceanic indicators suggest ongoing La Niña conditions in the equatorial Pacific (see El Niño Outlook updated on 11 January 2023).
- Monthly mean temperatures were below normal in eastern and western Japan. Monthly snowfall amounts were significantly above normal on the Sea of Japan side of eastern Japan.
- Monthly mean temperatures were extremely high from around the Mediterranean Sea to the northern part of Northern Africa and in the central part of South America, and extremely low in eastern Australia.
- Convective activity was enhanced from the eastern tropical Indian Ocean to near Southeast Asia, and suppressed over the western tropical Indian Ocean and the western to central tropical Pacific.
- In the 500-hPa height field over the Northern Hemisphere, the polar vortex split into the Siberian part and the North American part. Wave trains were dominant over the mid- and high-latitudes with positive anomalies near Alaska and southern Greenland, and negative anomalies near the eastern part of East Asia.
- In the sea level pressure field, the Siberian High was stronger than normal in the northwestern part, and the Aleutian Low was stronger than normal in the western part.

Full version (PDF)

Monthly Highlights on the Climate System (December 2022)
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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.

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