Significance
Basant Panchami heralds the arrival of spring and is dedicated to Goddess Saraswati, the deity of knowledge, music and the arts. Yellow — the colour of ripening mustard fields — dominates the day.
It is considered an abujh muhurat, an auspicious day in itself, favoured for beginning a child's education (vidyarambh) and other new starts.
Rituals
Saraswati is worshipped with yellow flowers, and students place their books, pens and instruments before her for blessings. People wear yellow, fly kites and prepare yellow sweets. In Bengal it is celebrated as Saraswati Puja.
How the date is fixed
It falls on the fifth tithi (Panchami) of the bright fortnight of Magha, hence "Panchami." The puja muhurat above is the auspicious span of the tithi for your location.