Today, Ganesh Chaturthi is observed in Bhadra month (August – September) in Bengal. But there was a time when Vinayaka Chaturthi was observed in Magh month (January – February). The day used to fall a day before Saraswati Puja or Sri Panchami (Basant Panchami). In Bengal, this specific date was historically more popular for Ganesha worship. Throughout the Bengal region, Ganesha used to be worshipped on this very date.
The reason could be that it was auspicious to worship Ganesha
first and then Goddess Saraswati on the next day.
The puranas also support this birthday celebration or Jayanti
of Ganpati. The Ganesha Khanda of the Brahma Vaivarta Purana states that Ganesha
was born as the son of Parvati (daughter of the Mountain King) and Maheshwara
through the will of Lord Vishnu himself on Magh Shukla Paksha Chaturthi.
A reference to the Magh month Ganesh Puja appears in
Satyajit Ray’s film Aparajito (1956), based on the story by Bibhutibhushan
Bandyopadhyay. In a letter to his mother, Apu writes, "There is no holiday
at college for Ganesh Puja. Besides, my exams are next month." The letter
is dated 13th Poush, 1333 (Bengali calendar). This suggests Apu was explaining
his inability to visit home by mentioning the lack of a holiday for the
upcoming Ganesh Puja in Magh. This serves as evidence that the tradition of
worshipping Ganesha on the Magh Shukla Chaturthi was once prevalent in Bengal.
Gradually, this practice has declined. However, in some
traditional aristocratic households (Bonedi Bari), Ganesha is still worshipped
on the Magh Shukla Chaturthi. For instance, in the Mallick household of
Bhowanipore in Kolkata, the Siddhidata is worshipped on the day before Sri
Panchami.