Tenki, Vol. 73, No. 1

(Tenki is the bulletin journal of the Meteorological Society of Japan in Japanese.)

TENKI, Vol. 73, No. 1, pp. 5-12, 2026

Regional Weather Zone Classification for Heavy Snowfalls in Japan

By
Ryo N. MATSUOKA*1 and Masaru INATSU*2

*1 (Corresponding author) Faculty of Science, Hokkaido University, N10W8, Kita-ku, Sapporo, Hokkaido, 060-0810, Japan.
matryo@ep.sci.hokudai.ac.jp
*2 Faculty of Science, Hokkaido University.

(Received 12 December 2024; Accepted 11 July 2025)

Abstract

We propose a regional weather classification in Japan based on heavy snowfalls. Self-Organizing Maps (SOM) are used to identify representative winter weather patterns, and the frequency of heavy snowfall occurrences for each pattern was calculated. Hierarchical clustering of these frequency distributions reveals eight distinct weather zones. The spatial distribution of these weather zones reveals the geographical systematicity of heavy snowfalls across the Japanese archipelago under the influence of the winter monsoon.