a man's heart is as fickle as autumn weather
Proverb comparing the changeability of a man's romantic feelings to the unpredictable autumn sky. Often contrasted with 女心と秋の空 (a woman's heart is as fickle as autumn weather).
See also: 女心と秋の空
As the saying goes, 'a man's heart is as fickle as autumn weather,' and his feelings changed in no time.
The female counterpart proverb, expressing the same idea about women's hearts. Both are used to comment on romantic fickleness.
A traditional Japanese proverb. The exact origin is uncertain, but it draws on the well-known variability of autumn weather in Japan as a metaphor for human emotions.