Is Navratri celebrated twice a year? If so, why?

Navratri is celebrated by Hindus from all over the world, but this is celebrated more in India. This is devoted to Maa Durga that they worship. The forms of worship may be different, but this is usually celebrated for nine nights. This is celebrated twice a year in order to signal the start of summer then it will be celebrated again at the beginning of winter.

The celebration during the start of summer is called Chaitra Navaratri, and the celebration at the beginning of winter is called Ashwina Navaratri. These are celebrated because this also shows the change that mother nature goes through and to make sure that equilibrium is maintained when the seasons change.