A conductor in a concert hall waves a single baton, yet the violins and timpani respond differently. Likewise, a warm patch in the Pacific Ocean, known as El Niño, makes different corners of Russia experience vastly different winters under the same phase. Somewhere, snow melts in January; elsewhere, frosts tighten their grip.

Meteorologists took 79 years of observational data, from 1936 to 2014, and split ten Russian regions into northern and southern groups. They compared each month's temperature against the norm, then looked at how often winters turned out mild or severe depending on what the Pacific was doing: warming, cooling, or staying neutral.

Transbaikalia behaves differently. When the Pacific warms, cold winters arrive there with a frequency of 0.75, while mild ones come only at 0.25. In other words, the same oceanic anomaly brings warmth to western Russia but chill to the east. Meanwhile, during the cold phase, known as La Niña, Transbaikalia saw not a single extremely cold winter over those 79 years. The winter of 2020/2021, which began right after a cold phase, confirmed this pattern: the region was warmer than normal.

A conductor cannot make timpani sound like violins, but he knows when each instrument will come in. So it is with El Niño: it does not dictate the weather entirely, but it hints at what to expect. And if in Transbaikalia you can skip the frost worries during the ocean's cold phase, then in the south of European Russia during the warm phase, you might want to stock up on umbrellas rather than boots.