Holī — the festival of colours
Phālguna Pūrṇimā (Holikā Dahana), colours the next day · February–March
Holī closes the lunar year on the full moon of Phālguna with fire and colour. On the night of the full moon, communities light the Holikā bonfire to remember Prahlāda's rescue and the burning away of what is harmful; the next morning (Dhuleṇḍī or Rangwālī Holī) everyone — young and old, neighbours and strangers — plays with coloured powder and water. It welcomes spring, the new wheat and barley, and a spirit of forgiveness: old quarrels are meant to be washed away with the colours.
At home, join or make a small Holikā Dahana at the time the panchang gives (outside bhadrā): walk around the fire, offer water, raw cotton thread, coconut, new grain ears and jaggery, and pray for the family's protection. The next day, touch elders' feet and put a little gulāl on their foreheads first, then play. Use natural, safe colours — turmeric, beetroot, henna, or ṭesū (palāśa) flowers soaked overnight — and avoid chemical, metallic or glass-mixed powders. Oil your skin and hair beforehand, protect eyes, never force colour on anyone, keep colour away from animals, and save water where you can. Guijiyā, malpuā, dahī-vaḍe and ṭhaṇḍāī are the festive foods.
Braj celebrates for weeks: Lāṭhmār Holī in Barsānā and Nandgaon, flower Holī in Vṛndāvan's temples. Bengal and Odisha keep Dol Jātrā / Dol Pūrṇimā, swinging Rādhā-Kṛṣṇa, and it is also Caitanya Mahāprabhu's birthday; Śāntiniketan holds Basanta Utsav. Goa's Śigmo and Manipur's Yaoshang add parades and sports; the Sikh Holā Mohallā at Anandpur Sahib follows the next day. In the South, Kāma-dahana remembers Śiva burning Kāmadeva. The Caribbean and Fiji call it Phagwah.
Tradition says that the asura king Hiraṇyakaśipu demanded to be worshipped as god, but his young son Prahlāda remained devoted to Viṣṇu despite every threat. The king's sister Holikā, said to be protected from fire, sat in a blazing pyre with Prahlāda on her lap — but the fire consumed her, and Prahlāda came out unharmed, chanting the name of Hari. Soon after, Viṣṇu appeared as Narasiṃha to end the tyrant's rule. The Holikā bonfire remembers that faith is not burned away.
In Braj, Holī belongs to Rādhā and Kṛṣṇa. Tradition tells that young Kṛṣṇa, dark-skinned, asked his mother Yaśodā why Rādhā was so fair; she playfully told him to colour Rādhā's face any colour he liked — and so began the play of colours among the cowherds of Vraja.
Viṣṇu (Narasiṃha) · Prahlāda · Rādhā-Kṛṣṇa · Holikā bonfire, then colours · Braj, Bengal Dol, Goa Śigmo, Phagwah · Bhāgavata Purāṇa 7 (Prahlāda)