What do you mean by sunrise in the east and rain in the west?

"Sunrise in the east and rain in the west, but sunny on the road" means:

It is sunny in the east and rainy in the west. I thought I was heartless, but I still have feelings.

original text

Four ancient folk songs with seven-character poems on love or local themes

Liu Yuxi

The willows in Jiang Shuiping are green, and I can hear the songs on the Langjiang River.

Sunrise in the east and rain in the west, the road is sunny.

translate

After a solar rain, the willows on both sides of the river are swaying and green, and the water level on the river is rising and calm as a mirror. The girl walked along the coast in depression. Suddenly, a melodious song came from the river with the wind. After listening carefully, it turned out that the lover who had not heard from him for a long time missed his love song. It's sunny in the east and rainy in the west, but she feels heartless.