According to the national calendar of India, Varsha Pratipada is the first day of the national calendar. Varsha Pratipada is also known as Gudi Padvo or Ugadi and falls at the beginning of spring on the first day of the month of Chaitra, which falls in April.
Spring or Vasanta Ritu traditionally brings optimism, hope and assurance to people about the future as it represents renewal. As Varsha Pratipada represents the beginning of a new year, it is also a time for self-reflection.

New Year and Tradition

Nationally, the day represents when the Barbaric tribes (shakas) who invaded India during the first century.
According to the national calendar of

Traditionally, in some parts of India neem leaves are mixed with jaggery (gour) and distributed on this day. The contrast between the bitterness of neem and the sweetness of jaggery signifies the conflicting aspects of human life - joy and sorrow, success and failure, ecstasy and agony. The neem-jaggery blend is also offered to God as naivedya and then distributed as prashada.

Shalivahana and Vikramaditya

Nationally, the day represents when the barbaric tribes (shakas and huns) who invaded India during the first century were defeated by the great emperors: Shalivahan and Vikramaditya. People who had become passive suddenly came to life and became patriotic, rising to the challenge of defeating the invaders.
The aforementioned Shalivahana was the King of Shatavaganas, whose capital Pratishtana was on the banks of the Godavari river (in Maharastra). The story goes that Shalivahana made clay soldiers and breathed life into them, in this way building a victorious army.
Another story says that Shalivahana worshipped the Goddess Kali, who thus represents the Hindu people rising to their heroic victory and crushing the foreign aggression of the shakas, and so Varsha Pratipada also signifies the triumph of divinity over wickedness.
Vikramaditya, meaning the 'sun of valour' (as Surya was the son of Aditi), was famous also for his courage during the time of the aggression. The King was crowned for his supreme sense of justice, so much so that Vikramaditya Simhaasana means the 'seat of undiluted justice'.
Thus naming the new eras Shalivahana and Vikram signifies the importance in Hindu history and tradition of safeguarding the nation's freedom and sovereignty. Both these Kings inspired their people, who had become passive following invasions and oppression. The two courageous kings effectively "breathed" back life into their people, giving them the courage that they had lost and the determination to fight for their nation. These eras symbolise the important task of protecting one's nation and are still cited today.

King Upricha and the Dhwaja
Another story behind Varsha Pratipada originates in the Mahabharat. During the time of the Pandavas, the evil King Upricha had been challenged to travel up to heaven. The story goes that he was actually victorious on this day as Lord Indra had given him a Dhwaja (flag) which he was to put outside his house. Therefore, on this day, people put up a Dhwaja outside their houses during daylight hours and pray for inspiration to keep the freedom of their nation intact.

Brahma-Dhwaja
Gudi Padwa is especially dedicated to the worship of Lord Brahma, as according to the Brahma Purana this is the day when Brahma created the world. This festival is also celebrated to commemorate the victory of Shree Rama over Bali. For these reasons the Gudi, Brahma's flag (Brahma-Dhwaja), is hoisted as a symbolic representation of Shree Rama's victory and happiness on returning to Ayodhya after slaying Ravan. Since a symbol of victory is always held high, so is the Gudi.