What does it mean to see frost for a hundred days in hot summer and rainy days?

If it rains cats and dogs in the summer solar term, the autumn cool will come earlier this year, the winter cold will come earlier, and frost will appear within 100 days.

In the eyes of farmers, heavy rain in summer solar terms is definitely not good, and sunny days in summer solar terms are better than rainy days. As the saying goes, "No summer heat, no grain", "No summer heat, no grain". It can be seen that if the weather is hot or not, the grain will fail, which farmers do not want to see.