MAIN WEATHER AND CLIMATE TRAITS IN THE NORTHEN HEMISPHERE AS OF OCTOBER 2021

Air Temperature

Cold September in the ETR gave way to a moderately cool October. In the first decade, the weather was abnormally cold in the southern and central Russia where the decade-averaged temperature anomalies reached -2…-4° or lower, with new daily minima recorded in the Smolensk, Tambov, Tula, Oryol, Belgorod and Moscow Regions as well as in the republics of Tatarstan and Udmurtia. In the second and third decades, the temperature returned to its normal value or even slightly above it everywhere save for the south: the frosts in the Southern and North Caucasian Federal Districts at the end of the month were as cold as -4…-10° or below. In general, frosts in the ETR were not uncommon in October, but the unprecedented temperature highs were also observed: for example, in the Murmansk Region and the Komi Republic in the north of the ETR in the first half of the month, and in the north-west and centre of the ETR in the second half of October.
This is in contrast to the territories east of the Urals. There, the temperature averages fluctuated around the normal figures in the third decade but overshoot them remarkably in the second and third ones: by as much as 6-11° or more in Siberia and Yakutia. New temperature maxima were repeatedly established both in the north and the east of Siberia, and in Yakutia. During the month, cold weather prevailed in the north of the Far East, but the south of this region was overwhelmed by extreme heat in the third decade. New temperature highs were repeatedly recorded in the Amur Region and in the south of the Khabarovsk Territory where the monthly-averaged temperature anomalies reached +3-4°or more.
As a result, the monthly-averaged air temperature was higher than normal in most of the country: by 2-3° and more in the European Territory, and by 4-6° and more in the Asian Territory of Russia. Sub-normal monthly averages were measured in the north-east of the country, as well as in the south of the ETR. And as for the federal districts, the monthly-averaged temperature turned out to be lower than normal in the North Caucasian Federal District only, and was either normal or increased in all the other ones.
The monthly-averaged temperatures in most of East Asia were close to normal, with the exception of some locations where the normal values were exceeded in the south-west of China in the provinces of Yunnan and Sichuan, and in the north of Japan. In Japan, the unprecedented high temperatures were recorded in the first decade of the month: the thermometer readings rose above 30° sometimes. Conversely, the Korean Peninsula and the east of China were hit by bitter colds in the middle of the month, and new temperature minima down to -10° or below were established in these areas.
MAIN WEATHER AND CLIMATE TRAITS IN THE NORTHEN HEMISPHERE AS OF SEPTEMBER 2021

Air Temperature

Abnormally hot summer in the European Territory of Russia gave way to cold autumn in the first days of September. Frosts in the areas from Murmansk to Volgograd came as early as on the fifth of the month, and occurred again and again since then. The average air temperature was 2-3 or more degrees below normal in the first decade. The overall picture remained about the same later on, but the colds were spreading far and wide to occupy almost all Russia by the end of the month, save for the south of the Far East and the Arctic region. The record-breaking colds were observed in the north of the ETR, in the south of the Urals, in the north of West Siberia and in Chukotka. At the end of the month, 20-degree frosts reached Yakutia already, and the cold spells haunting the ETR came to Tyva, Khakassia, to Irkutsk, Chelyabinsk and Kurgan Regions, and to other areas of Russia as well. The Arctic territories and the south of the Far Eastern Federal District were the only regions where new maxima of air temperature were recorded.
As a result, this September became the coldest in the ETR for the past 25 years since 1996, and hence the coldest one in the 21st century. The monthly-averaged air temperature was less than normal all over Russia. Even though the weather in the Asian Territory of Russia was sometimes much colder than usual, it changed to warmth from time to time, and the monthly-averaged air temperature turned out to be close to normal both in the Asian Territory and in Russia as a whole. This temperature was less than normal in all federal districts of the ETR, close to normal in the Urals and Siberian ones as well as in the north of the Far Eastern Federal District, and higher than normal, remarkably higher indeed, in the south of the latter District. The average air temperature of September 2021 in the south of the Far East was at the third place in the list of highest historical values, yielding to September 2020 and September 1959 only.
In the east and south-east of Asia, this month was warmer than usual, notably in China and Mongolia where the monthly-averaged temperatures exceeded their normal values by 2-4° or more. This September was the hottest in the meteorological history of China, with the previous record of 2005 overridden by as much as 0.5°.