Seasonal Reversal of Polarity Dominance in High‐Current Cloud‐to‐Ground Return Strokes Over East Asian Midlatitudes

Abstract

Abstract Extreme positive cloud‐to‐ground lightning over East Asian midlatitudes exhibits a spring–autumn double maximum hidden by the familiar winter climatology. Using 1,838,538 return strokes with absolute peak currents at least 200 kA during 2006–2024, we resolve its annual cycle by month and latitude. At 35–55N, positive strokes account for 86.2% in April and 77.1% in October and remain dominant from September through November; negative strokes dominate in winter and midsummer. The contrast arises primarily within latitude bands and strengthens with current: positive strokes are 28.3 and 23.7 times more likely than negative strokes to exceed 200 kA in April and October. April dominance spans cloud environments, whereas October dominance collapses above 9‐km cloud tops and accompanies freezing levels 0.3–0.4 km lower. This twice‐yearly reversal links the polarity of extreme ground lightning to seasonally changing current distributions and storm vertical structure.