What does "thunder in summer, Huangmei upside down" mean?

"When it thunders in midsummer, plum blossoms hang upside down" is a popular meteorological proverb, which means that after the rainy season, if there is thunder in the "midsummer" solar terms, the rainy season will hang upside down. Simply put, if the solar terms thunder in summer, then the rainy season may come again.

The average rainy day is around the end of May, and then the weather will become more and more stable. Thunderstorm is a symbol of unstable weather, which shows that cold air southward affects the Yangtze River basin and is conducive to the re-establishment of rain belts in the middle and lower reaches of the Yangtze River.

It's a proverb that it thunders in summer but it pours yellow plum. This means that if thunder rumbles in summer, it indicates that a flood disaster is coming.

There is also a proverb, "Huangmei falls upside down when it thunders in a small summer", which means that the weather is bad in a small summer, and it may rain next time, that is, "Huangmei hangs upside down".