Note: The dates bracketed in English for each festival will vary each year because they are celebrated according to the Indian Calendar which is based on lunar days.
The Diwali festival lasts for a period of five days.

Dhan Teras
The first, celebrated even today, is called Dhanteras.
This falls on the thirteenth day of the dark half of the month of Aaso. On this day people worship (do pujan) their new account books as well as do pujan of Lakshmi - the goddess of wealth.
The significance of this occasion is to remind and ensure that you behold money as a 'devi' - a goddess, and spend it for auspicious and charitable purposes. It should be respected and not squandered or spent to cause one's ruin or that of another.

Kaali Chaudasha
The second occasion, is a day on which Hanumanji is specially worshipped. People normally serve the Brahmins with special delicacies in honor of their dead relatives. Prayers are also chanted to appease the gods and to cast off any evil influence. It was on this day that Lord Krishna killed the demon called Naraka. The story of the Lord's battle with him is found in the Shrimad Bhagvata. It describes how Narakaasura, the king of Praagjyhotishapur, unleashed a reign of terror on earth and in the heavens. He is believed to have conquered and plundered the earth and heavens. He carried away sixteen thousand daughters of the gods and imprisoned them in his mountain haunt. He also robbed Aditi, the mother of the gods, of her ornamental earrings. This last act was the final straw. The gods supplicated to Lord Krishna to come and destroy Narakaasura. In reply to their earnest pleading Lord Krishna marched to the city of Praagjyhotishpur. He scaled the mountainous region, waded through the red waters of a river and ripped open the wall protecting the mighty citadel. The Lord battled with the demons before finally plunging into the nether regions (Paataala). It was here that a fierce encounter raged between the Lord and Narakaasura. The three worlds trembled when the demon hurled his powerful weapon called Shakti at the Lord. But the Lord remained unscathed. Naraka flew into a frenzy and was about to deal his final blow when the Lord cut his head asunder with his powerful disc, 'Sudershan Chakra'. Narakaasura had been destroyed. The Earth handed over the earrings of Aditi to the Lord. The Lord freed the damsels from their shackles and at their wishes accepted them as His wives. This day of victory is popularly known as 'Naraka Chaturdashi.'

Diwali Day:
This is the last day of the year in the Indian calendar. People invariably light their homes with lamps and enjoy a display of firecrackers. Beautiful 'rangoli' decorations on doorsteps welcome guests. People visit and greet one another, sweets and gifts are exchanged.
The air of joy and happiness reflects each year that this was the day when the earth and her people were delivered from the clutches of the demon Naraka. Diwali is a day of victory of good over evil, a celebration of good over evil.

New Year's Day
The first day of the Indian year was a day when the citizens of Gokula in the time of Lord Krishna, collected their harvest and offered their appreciations to Indra, the rain god. Lord Krishna did not approve of this. He felt that rather than take refugee in the gods which would only reward them with worldly pleasures, it would be far more profitable to take refuge in God and be blessed with the eternal bliss of the Supreme. The Lord convinced his father and elders of the village to stop worshipping Indra. By his wishes everyone offered sweets and vegetables to a mountain called Govardhan. The villagers felt the Lord accepted their offerings through the mountain. When Indra came to know of this he flew into a terrible rage. He ruthlessly rained over Gokula, destroying many homes and cattle. People were left exposed to the bitter wrath of Indra, homeless and helpless. This drastic turn of fate they attributed to their not having worshipped Indra. The Lord observed that the ignorant shepherds still owed their faith and allegiance to Indra. They were unaware of the fact that the strength of the gods paled into insignificance when it came to comparing them with the Ultimate Being. To convince them of this truth the Lord lifted Mt.Govardhan with the tip of his smallest finger. The villagers having no other refuge then that of God immediately rushed beneath the mountain. And since then the custom of savoury offerings of food to the Lord began. It is now popularly known as Annakut Festival.

Dev Diwali
The last day of 'Chaaturmaas' is Kartik Sud Ekadashi. This day too has been flagged as an important day because once again we find the Lord subduing evil forces. On this day the demon Jalandhar was destroyed by Lord Vishnu through blemishing the chastity of Vrunda, Jalandhar's wife. It was believed that the demon's invincibility was due to his wife Vrunda's fidelity. When the Lord shattered her fidelity, Jalandhar died. The Lord married Vrunda. After her demise she was reborn as a basil plant and hence the offering of basil leaves while worshipping Lord Vishnu. One this day, people light lamps to honour it as the day when Lord Vishnu married Vrunda and hence it is called 'Dev Diwali. Dev Diwali is also known as Prabhodini Ekadashi. On this day the Lord awakens from his slumber in Kshirsagar, ocean of milk. This is the day when the Lord leaves, after having stayed for four months with Bali, for His abode. In front of the Lord are placed a variety of vegetables. From this day, one can have vegetables that were abstained from during the four months.
On Dev Diwali, the four holy months of 'Chaaturmaas' come to an end. In the Bhavishya Purana it has been said that one who sincerely fulfils and celebrates the four holy months is blessed with the Lord's proximity.