The main weather and climate features of the northern hemisphere in May 2017

Air Temperature.

The last May of the European territory of Russia (ETR) will come to mind for the population for a long time as a cold and rainy. The often intrusions of the Arctic cold caused the record colds and even frosts during all month. The average monthly air temperature was below the norm in all federal districts. In Central Russia – approximately by 2°, in the Russian North – up to 4°. Almost daily somewhere the new minimum temperature records were registered. The negative temperature anomalies in May, similar to the present ones, were observed here the last time in 2008, and in general every decade in the Russian Plain was marked with at least one such cold May. Sometimes it has happened even more frequently. For instance, during the 90th of the last century it has happened triple times over the decade (in 1990, 1994 and 1999).
In Siberia and most part of Far East the warmth and cold swapped each other. Instead of the heat of 25-30° (Republic Tuva, Transbaikalia, Irkutsk district) frosts 
of -10° and colder came (south of West Siberia, Republic Tuva, Altai, south of Krasnoyarsk district). As a result, the average monthly air temperature in the most part of these areas was close to the norm, with small negative anomalies in Yakutia and with positive ones in the other territory. And only in Kemerovo region, in Altai and Tuva Republics and Chukchi Autonomous District and Jewish Autonomous Region the temperature norms were noticeably exceeded (by 2° and more).
The hot weather dominated in the east of Asia. In Beijing the air temperature reached +37°. In the north of the country, in Japan and Korean peninsula the average monthly air temperatures exceeded the norm by 2-3°, in Mongolia – by 3-5°. In China the last May is the third warmest one on the record after 2007 and 2012.


The main weather and climate features of the northern hemisphere in April 2017

Air Temperature

In the European territory of Russia (ETR) the temperature conditions were substantially different. In the first ten-day period the March abnormally warm weather was kept. In the north-west and centre of ETU the air temperature anomalies over the first decade reached +3…6 and more. Here were the numerous warm records: Kaliningrad, Pskov, Smolensk, Bryansk, etc. But in the second ten days cold penetrated here, and ten-days period temperature anomalies have set -2…-3°. In the third decade the cold reached the south Russian border. Average decade temperature anomalies exceeded -3…-4°. In the west and central ETR regions, in Volga area and in the south (Crimea, Krasnodar, Stavropol districts) the new daily temperature minimums were achieved. In Smolensk district the frosts reached -15°, Tambov - -9°, the light frosts were even in the south – Rostov district, Stavropol district and in Republic of North Ossetia-Alania. The warmth came to the Central Russia only in the last day of the month.

Striking contrast of ETR became the temperature on the east of Urals. If in Urals, particularly its northern part, in the first and second decade the temperature conditions corresponded to the norm, and abnormal warmth came here only in the third decade, but in Siberia and in Far East it dominated all month long. The average decade temperature anomalies reached here +7…8°. In the north of Far East the April 2017 is the warmest on the country record. In Siberia, seven out of ten warmest Aprils occured in XXI century.