Why do many people migrate to an urban area, pick up a job and stay there for some time, but come back to their home villages as soon as the rainy season begins?

Work in agriculture is seasonal

Many people migrate to an urban area, pick up a job and stay there for some time, but come back to their home villages as soon as the rainy season begins. This is because work in agriculture is seasonal; there are no employment opportunities in the village for all months in the year. When there is no work to do on farms, people go to urban areas and look for jobs. This kind of unemployment is known as seasonal unemployment. This is also a common form of unemployment prevailing in India.