Halloween is holiday celebration that occurs every year on the 31st of October, and the 2019 Halloween date is Thursday, October 31.
Its a day set aside originally for the ancient Celtic festival of Samhain, a festival day when people would light bonfires and wear costumes to ward off ghosts. It is with regards to the christian belief of the eve of welcoming all saints and the night or day of warding of all ghosts or evil spirit. That is why we have all saints day as November 1st in the christian calendar.
People usually dress in stylish scaring ways to ward off ghosts on this day.