In Moscow the average temperature over the last 17 days is 8.5 ° C.

On some days in May, negative temperature anomalies reached 9-10ºC below average. In recent days the average temperature “behind” the standard of 6.1ºC.

This makes it the coldest May in Moscow since 1918.

Records in Moscow have been kept since 1879.

http://hmn.ru/index.php?index=1&ts=170518110240

Thanks to Martin Siebert for this link