MAIN WEATHER AND CLIMATE TRAITS IN THE NORTHERN HEMISPHERE AS OF OCTOBER 2025
Air Temperature
In the ETR, the average air temperature in the first decade of October was basically normal except for the Russian North where the weather was noticeably warmer than usual. New daily temperature maxima were even recorded in Karelia and in the Astrakhan Region. At the end of the decade, flows of hot air from the Middle East reached North Caucasus where new maxima of warmth were set in some places as well. Conversely, new record-breaking air temperature minima were reported in the Black Earth Region, in some locations of the Volga region and in the north-west of the ETR at the beginning of the month.
In the second decade, cold weather arrived: not bitterly cold, but still bringing frosts to Crimea in particular. Overall, conditions in the ETR during the decade remained close to normal, albeit that with weakly-negative anomalies occupying a large territory.
Abnormal warmth came forth in the ETR in the third decade, when the average temperature became above-normal almost everywhere: in the Central and Volga regions as well as in the north-west, the decade-averaged anomalies of air temperature exceeded +2-3°.
In the Urals and to the east of them, the first decade was cold, with the average temperature 2-4° less than normal over a large area. The weather in the second decade became yet colder, with anomalies reaching -5…-6° in some places. Record-breaking minima of air temperature were recorded in the south of Western Siberia, e.g., in the Omsk and Novosibirsk Regions, in the Republic of Altai, in Cis-Baikal and Trans-Baikal, on Sakhalin and in the Khabarovsk Territory. First 30-35° frosts came to Yakutia and Chukotka.
MAIN WEATHER AND CLIMATE TRAITS IN THE NORTHERN HEMISPHERE AS OF SEPTEMBER 2025
Air Temperature
With the beginning of September, summer returned to the ETR. In the first decade, average air temperatures became above-normal everywhere, 2-3° higher than normal in the north and west, as well as in the Caucasus. New temperature maxima were recorded in Karelia and Central Russia to exceed 30° in some places, and temperatures as high as that were measured in the Luhansk Region. In the second decade, temperature anomalies in the north and west of the ETR became even higher, reaching 4-6° or more degrees in the Russian North. New daily temperature highs were set in the Arkhangelsk and Murmansk Regions as well as in the Komi Republic. Meanwhile, temperatures in Central Russia returned to normal, while in some locations in the south, the average temperature for the second decade became even less than normal. In the third decade, no high positive temperature anomalies were detected in the ETR: the decade-averaged air temperatures were close to normal almost everywhere, or even sub-normal on the Black Sea coast of the Caucasus. In the last days of the month, frosts were observed, down to -7° in the south, and new daily temperature lows were set.
In the Urals, the weather remained warm until mid-month, with anomalies higher than 2-4° in the north. In the second decade, first frosts came there to the south, and in the third, record-breaking colds to the north.
The weather in Siberia kept up abnormally warm for almost the entire first decade; then, cold air masses started to dominate in the north, and warm ones, in the south. As a result, the average air temperature in the second and third decades in the north was 1-4 or more degrees below normal, whereas in the south, it was about the same value above that. At the end of the month, new temperature highs were set in the Omsk, Tomsk and Irkutsk Regions.