The abnormal colds which occupied the northern and central regions of the ETR in the last decade of November intensified even more at the beginning of December. In the first decade, the air temperature was short of 6-10° to reach its normal value. The thermometer readings dropped to -35° in Karelia and to -40° or below in Udmurtia, Bashkiria and the Perm Territory, with new daily minima of air temperatures recorded in the Volga region. A sharp break of temperature patterns occurred in the middle of the month and brought anomalous heat that prevailed across the whole ETR in the third decade. New daily temperature maxima were measured at times everywhere from the Volga to the Urals.

The reign of cold in the first and second decades extended beyond the Urals: the average temperatures were 6-12° below normal in the south of Siberia, and the recorded frosts were colder than -40° in Western Siberia, in the Irkutsk Region, in the Trans-Baikal and in the Primorye Territory, than -50° in Kolyma, and than -60° in Yakutia. New daily temperature minima were set in Buryatia, in the Trans-Baikal Territory, and on Sakhalin.

In the third decade, these anomalous colds survived in the Far East only where the temperature averages were 4-8° below normal in Yakutia, Kolyma and the Khabarovsk Territory, in contrast to Siberia where anomalous warmth came to set new daily temperature maxima in the south and in Yakutia. In the midst of winter, the thermometers in the Khabarovsk Territory showed above +5°.

On the average, the weather in December was abnormally warm in the south of the ETR, in the north of the Urals and along the Arctic coast; there, the monthly-averaged temperatures were 2-4° higher than normal. Subnormal temperatures were measured in the northern regions of the ETR, in the south of Siberia and in the Far East. And as a result, the air temperature in December monthly-averaged over the entire country was close to normal.

After the final month of 2023, this year can eventually be called very warm in Russia: the resulting annual figures for air temperatures were higher than normal everywhere except for small coastal areas of Chukotka, 1-2 or more degrees higher in most of the ETR, in the Urals and in Western Siberia.

The average temperature of 2023 was ranked the third highest in the meteorological chronicle since 1891. Still, three more years, viz., 2007, 2017 and 2018, were awarded the same rank, following yet invincible 2020 and 2022 after it. This year was the second warmest in the ETR, the warmest in the Southern, North-Caucasian and Volga Federal Districts, and the second warmest again in the Urals Federal District. And in general, the average temperature of 2023 was among the top ten high-ranked ones in all federal districts of the country.

In East Asia, this December was warm. The monthly-averaged air temperatures in most of China, in Japan and in the Korean Peninsula were either close to normal, or slightly above that. The north-east of China was the only area where the weather was abnormally cold: there, new daily minima of air temperature were set for several days in succession, some of them as low as -40…-45°. Similar frosts persisted in neighbouring Mongolia.

The month in the countries of South-East Asia was notably warmer than usual: the monthly-averaged temperatures over a large area were two or more degrees higher than normal.

The temperatures in India and Pakistan were close to normal.

The countries of Central Asia as well as of the Near and Middle East received above-normal heat this December. The monthly-averaged temperature anomalies all over the territory were +2…4° or higher. In Kazakhstan and in the countries of Central Asia, unprecedented temperatures were recorded at the end of the month, and the thermometers indicated above +25° in some places.

The monthly-averaged temperatures everywhere in North Africa were higher than normal, two or more degrees higher in the north-east and in the west. This December, alongside those of 1990 and 2009, was the second warmest in the meteorological history of the continent, December 2022 being the only one even warmer.

In North Europe, winter came early, bringing sub-normal air temperatures at the end of November, and setting new December temperature minima in the Scandinavian countries where the thermometers dropped below -30…-35° at times and the resulting monthly averages were two or more degrees lower than usual. But the rest of the continent received noticeably more heat than normal: in France and Italy, for example, new temperature maxima were recorded for several days in a row, and the air would warm up above 25°. The unprecedented daily highs were measured in England, Switzerland, Italy, Greece and Hungary. The average air temperatures in Central and Western Europe were two or more degrees higher than the normal values.

This December in North America was so warm as to become the warmest in history of Canada and of the United States. The monthly-averaged air temperature was 2-8° greater than normal in Canada and everywhere in the USA except for Alaska. New maxima of monthly-averaged air temperatures in December were reached in the northern US states of Montana, North and South Dakota, Nebraska, Minnesota and Wisconsin. In Alaska, the anomalies were negative, down to -2°.

December 2023 in the Arctic was the second warmest in history, December 2017 being the only one even warmer.

As for the entire Northern Hemisphere, this December was the warmest in the meteorological annals. Its annual average temperature was more than 0.2° higher than the previous achievement recorded in 2020, and more than 0.4° higher than it was a year ago in 2022. No such impetuous increase in annual averages has been ever observed before, and – based on some indications – the recently started 2024 would be even warmer. In 2023, the average air temperature was higher than normal in all continents, in particular, by 2-3 or more degrees higher in Canada and by 2° higher in the north of the Urals and in some parts of Kazakhstan. The only places were the weather was colder than usual were Alaska and certain water areas of the World Ocean: the eastern part of the Pacific Ocean to some extent, the Bering Sea and the north Atlantic. The year 2023 was the warmest in the history of China, the second warmest, of Canada, Europe and North Africa, and the third warmest, of the United States.

The monthly-averaged temperature in Moscow was -4.4°, which is normal. In the annual terms, 2023 was the third warmest in the meteorological chronicle, with 2020 and 2019 being the only years even warmer.

 

El Niño was still acting and growing in strength in the east of the equatorial latitudes of the Pacific Ocean. From its initiation this May until this December, the average SST anomaly in the El Niño zone increased by 1.4° from 0.5° to 1.9°. The anomalies closer to the equator exceeded 2°. The SST anomalies were positive almost throughout the entire Pacific Ocean in the Northern Hemisphere, save for the water areas east of the Islands of Japan as well as in the Sea of Okhotsk and off the coast of Alaska. The SST of the Pacific Ocean in the Northern Hemisphere reached its maximum and reproduced the value achieved in December 2020.

The Atlantic Ocean in the Northern Hemisphere was also very warm, especially at the equatorial and tropical latitudes where anomalies even exceeded +2°. Sub-normal SST values were only measured in part of the Greenland Sea and east of Newfoundland. In December 2023, the average SST of the Atlantic Ocean in the Northern Hemisphere reached the absolute maximum.

In 2023, the annual SST anomalies averaged over the surfaces of both the Pacific and Atlantic Oceans in the Northern Hemisphere reached the absolute maxima. The anomalies were positive over their entire surface of the oceans, amounting up to 1.5-2.0°. In the history of regular observations, the surface of oceans in the Northern Hemisphere has never been so warm before.

Almost everywhere in the ETR, precipitation was normal or increased, with the exception of the Nenets Autonomous District where less than 50% of the normal precipitation amount accumulated in December. During the month, a number of record-breaking snowfalls occurred in Central Russia, in the Volga region, in the Lower Volga and in the Crimea; each day, they brought up to or more than 30 mm of precipitation and increased the snow cover height by 20-40 cm. New maxima of daily precipitation totals were recorded here and there. At the end of the month, the normal monthly amount fell in the Southern Urals for a day and a half, building snow banks half a metre high that have not been seen there for the quarter of a century before, and leading to a traffic collapse. The normal monthly quantities in some regions of the Central Federal District were exceeded by two or more times; the same happened in the regions of the Southern Urals.

Heavy snowfalls passed in the continental regions of the Far East where the normal monthly precipitation amounts were exceeded by 1.5-2.5 or more times in places. At the same time, the Primorye Territory, Kamchatka and Chukotka received less precipitation than expected, less than half of the normal quantity as a rule.

The central and north-eastern provinces of China were also targeted by heavy snowfalls. In places, the normal seasonal precipitation amount fell during a couple of days. The normal monthly values were exceeded by 2-3 or more times.

Heavy downpours hit the southern regions of Thailand, led to catastrophic landslides, disrupted traffic circulation and blocked transportation of agricultural products in the north-south direction.

The eastern coast of India and the Republic of Sri Lanka were allotted a great deal more precipitation than normal. Some settlements in the low lands were flooded, and the railway traffic was stopped. The authorities termed this flood as unprecedented. 50-70 mm of rainwater would fall per day.

The weather in the Near and Middle East as well as in most of Central Asia apart from Transcaucasia and the northern regions of Kazakhstan was dry.

Dryness reigned in most of North Africa as well. Rains fell in individual locations along the Mediterranean coast, and in the east of Kenya where they caused floods and massive destruction of the infrastructure in this territory, killing people.

Heavy snowfalls took place in Northern and Central Europe. In the Alps, the height of snow cover exceeded 70 cm as early as at the beginning of the month. The normal monthly precipitation amount was reached or exceeded in this part of the continent. The weather in the south was dry, whereas in Belarus and Ukraine, the precipitation amounts were record-breaking.

The precipitation amounts in most of Canada were subnormal, and reached the normal values in the east of the country, similar to the eastern coast of the USA where a lot of precipitation went to the central states.

As for the whole year 2023, its annual precipitation totals in most of the Northern Hemisphere were either normal, or somewhat increased in a number of regions in the south of Russia and in Siberia. In foreign countries, precipitation in terms of the annual figures was above-normal in the north-eastern regions of China, partially on the coast of North Africa, and in certain western US areas. Subnormal precipitation was observed in most of Central Asia, in the Near and Middle East, as well as in North Africa, southern Europe, Canada, southern United States, Mexico and the countries of Central America. Terrible drought invaded Ethiopia.

In December, 89 mm of atmospheric moisture fell in Moscow, amounting to 174% of the normal value. As a result, this was the third wettest December in the capital since 1891: the December totals were higher in 2022 and 1981 only. As for the annual figure, 833 mm of precipitation fell in the capital, which is 117% of the normal amount. Eventually, 2023 became the twelfth wettest year since 1891. The record high equal to 891 mm belongs to 2013.