In Buddhism what does the rainy season retreat remember?

Answer 1

The "rainy season retreat" or practice period, sometimes called, "Ango" in the Mahayana, recalls the life of the historical Buddha and his followers. He and his followers, or "Sangha" walked from village to village begging their food and practicing mindfulness. That was their practice. In India, the monsoons are so intense it wasn't practical to do the walking meditation duing that time, so during the monsoons they would gather somehwere they could sit and ask questions. The Sutras were written on the basis of the Q&A's during the rainy season practice periods.