Pūrṇimā vrata is the monthly full-moon fast, kept on the day the full Moon stands in the evening sky. Because the vow follows the rising Moon, the evening is its heart. Depending on the month and the house, the day may bring a Satyanārāyaṇa pūjā, a lamp lit for the Moon, or simply the fast itself. How the day is fixed: The vrata falls on the one civil day when Pūrṇimā is running at moonrise. If the tithi begins on Caturdaśī and already covers that evening's moonrise, the fast is kept that day. Keep in mind: If Pūrṇimā misses both moonrises, the day with Pūrṇimā at sunrise is taken. Check the moonrise time in the day's pañcāṅga before you fix the fast. This year: The 2026 date shown here is worked out from sunrise at the place you chose, so in another city the same day can fall a day earlier or later. Satyanārāyaṇa pūjā: In many homes the full moon is the day for Satyanārāyaṇa pūjā. Which rite is kept depends on the month and on the family. A lamp for the Moon: Other homes light a lamp for the Moon once it rises. Some keep only the fast, with no separate pūjā. Worth remembering: Guru, Śarad, Nāralī, Kumāra and Kojāgarī Pūrṇimā are named full moons, each observed in its own right. Nāralī Pūrṇimā and Rakṣābandhana can share the Śrāvaṇa full moon, but both are separate from this monthly vrata. Each month's full moon carries a different colour in different regions, and families add their own vows to it. What one house keeps as a quiet fast another keeps with a full kathā. Follow the custom that the elders of your own house have kept.