Basant Panchmi , Saraswati Puja
Basant Panchmi is celebrated on the fifth day (Panchami Tithi) of the bright fortnight (Shukla Paksha) of the Hindu month Magh. From this day, Vasant Ritu (the spring season) begins in India. Saraswati Puja is also performed on this day. The celebration takes place when the Panchami Tithi prevails during the first half of the day i.e. the time between sunrise and midday.
If Panchmi Tithi begins after the midday and prevails in the first half of the next day then Vasant Panchami is celebrated on the second day. The celebration can only shift to the next day in one condition i.e. if Panchami TIthi is not prevailing in the first half of the first day at any point of time. Otherwise, in all other cases, the celebration will take place on the first day. That is why, sometimes, Basant Panchami also falls on the Chaturthi Tithi as per Panchang.
On this day, Goddess Rati and Lord Kamdev are worshiped in 16 ways (Shodhashopchar Puja) during the first half of this day i.e. the time between sunrise till midday.