Lohri is the Punjabis cultural celebration on the eve of the winter solstice. However, instead of celebrating Lohri on the eve of winter solstice, Punjabis celebrate it on the last day of the month during which winter solstice takes place, Paush as no sacred festival is celebrated in the month of Paush as per the Brahmins. This is due to linking Lohri to the Bikrami calendar. Among Sindhi's the festival is popularly known as Lal loee. On the day of Lal Loee kids bring wood sticks from their grand parents and aunties and like a fire camp burnt these sticks in the night with people enjoying, dancing and playing around fire
According to folk lore, in ancient Punjab Lohri was celebrated on the eve of winter solstice day. It is for this reason that people believe the Lohri night is meant to be the longest night of the year and on the day after Lohri, day light is meant to increase.
However, scientifically, the shortest day of the year is around December 21'22 after when the days begin to get longer. Accordingly, winter solstice begins on December 21 or December 22 and Lohri ought to be celebrated a day before winter solstice.