The article presents the study results of the annual variability of thunderstorm activity at nine climatic stations in Western Siberia over a fifty-year period from 1971 to 2020. The study revealed a complex quasi-periodic structure of thunderstorm activity series with the most pronounced amplitude of 7–8-year cycles for the forest-tundra and a 2–4-year cycle for the taiga zone, as well as forest-steppes. A synchronous course of increase and decrease periods in the frequency of thunderstorms for individual decades at the studied climatic stations in Western Siberia was revealed.