This article relies largely or entirely on a single source. (March 2015)
Panguni Uthiram (Tamil:பங்குனி உத்திரம்) (also known as Meena Uttara-phalguni in Sanskrit) is a day of importance to Tamil Hindus. It falls on the day the moon transits in the asterism or nakshatram of Uttara-phalguni or Uthiram in the twelfth month of the Tamil solar calendar i.e. Panguni (March–April). It is the full moon of the month of Panguni.
This month is special because the Uthiram nakshatram coincides with the full moon. This full moon signifies the marriage of Parvati and Parameswara (Lord Shiva), Murugan and Deivanai, and Aandaal (also known as Kothai) and Rangamannar took place. On Panguni Uthiram, Narayana marries Komalavalli Naachiyar and give his Kalyana Kola Seva to his Bhakthas. Again, Valmiki's Ramayana says it is on this day and star that Sita's marriage with Rama was celebrated. From Brahmanda Puranam we learn that on Panguni Uthiram every holy water joins Thumburu teertha (also spelt as Tirtha), one of seven sacred tanks in Tirupati Tirumala.
The day is intended to underline the glory of grahasta dharma (or the married life of a householder). The Almighty manifests in the marital state as Uma Maheswara, Sita Rama, and Radha Krishna – despite his changelessness, sans childhood or youth or old age. The Lord is indeed a Nitya Kalyana Murthi. It is our duty to celebrate this day when the Lord, in both Shiva and Vishnu temples, appears to devotees in his married state. On Panguni Uthiram, in all places where Lord Subrahmanya has a temple, his devotees carry in a kavadi the requisites for puja for him, in fulfilment of vows. Such vow fulfilment by devotees carrying kavadis is a special feature of Subrahmanya temples wherever they happen to be.
Devotees flock in hundreds to the all Murugan temples during the Panguni Uthiram festival, which is celebrated in March every year. It is the Jayanti (Day of Incarnation) of Lord Ayyappan. It is also an important festival day for Lord Subramanya (Muruga), as it is on this day that Sri Deivanai married Lord Subramanya. On this day Goddess Mahalakshmi incarnated on earth from the ocean of milk (after the ocean was churned by the Gods and the demons) and hence it is celebrated as Mahalakshmi Jayanti. On this day Goddess Parvati in the form of Gowri married Lord Siva in Kanchipuram and hence this day is also celebrated as the Gowri Kalyanam day.
Other Significances of the day
This Phalgun Poornima day is also Holi in the Braj region, which includes locations traditionally connected to the Lord Krishna: Mathura, Vrindavan, Nandagaon, and Barsana, Kumaoni (Uttarakhant). The day that Holika the sister of Hiranyakashibu was destroyed. It is celebrated as Basatotsav (Bengal), Phagwah (Bihar), Doḷajātra (Oriya), Ganga Mela (UP), Dol Purnima (Bengal), Śigmo (Konkani), Rangapanchami (MP), Yaosang (Manipur), Basnata Panchami (AP), Phakuwa (Assam), Shimga (Maharashtra), Manjal Kuli (Kerala), Fagu Poornima (Nepal), Panguni Uthram Vasanthotsavam (TN). The playful throwing of natural coloured powders has a medicinal significance: the colours are traditionally made of Neem, Kumkum, Haldi, Bilva, and other medicinal herbs prescribed by Āyurvedic doctors. A very auspicious day for all Hindus.