Uposatha Observance Days

For monastics, these are often days of more intensive reflection and meditation. In many monasteries physical labor (construction projects, repairs, etc.) is curtailed. On New Moon and Full Moon days the fortnightly confession and recitation of the Patimokkha (monastic rules of conduct) takes place.

Lay people observe the eight precepts on Uposatha days, as a support for meditation practice and as a way to re-energize commitment to the Dhamma. Whenever possible, lay people use these days as an opportunity to visit the local monastery, in order to make special offerings to the Sangha, to listen to Dhamma, and to practice meditation with Dhamma companions late into the night. For laity not closely affiliated with a local monastery, it can simply be an opportunity to increase one's efforts in meditation while drawing on the invisible support of millions of other practicing Buddhists around the world.

The calendar of Uposatha days is calculated using a complicated traditional formula that is only loosely based on the astronomical (lunar) calendar, with the result that the dates do not always coincide with the actual astronomical dates. To further confuse matters, each sect within Theravada Buddhism tends to follow its own calendar.

The calendar below lists the Uposatha days that will be observed in the coming year by followers of the Mahanikaya sect of Thai Buddhism.

Uposatha observance days (1999-2000)
Last Quarter	New Moon	First Quarter	Full Moon
Nov 30, 1999	Dec 7, 1999	Dec 15, 1999	Dec 22, 1999
Dec 30, 1999	Jan 5, 2000	Jan 13	Jan 20
Jan 28	Feb 4	Feb 12	Feb 19 Magha Puja
Feb 27	Mar 4	Mar 12	Mar 19
Mar 27	Apr 3	Apr 11	Apr 18
Apr 26	May 2	May 10	May 17 Visakha Puja
May 25	Jun 1	Jun 9	Jun 16
Jun 24	Jul 1	Jul 9	Jul 16 Asalha Puja
Jul 24	Jul 31	Aug 8	Aug 15
Aug 23	Aug 29	Sep 6	Sep 13
Sep 21	Sep 28	Oct 6	Oct 13 Pavarana Day
Oct 21	Oct 27	Nov 4	Nov 11 Anapanasati Day
Nov 19	Nov 26	Dec 4	Dec 11
Dec 19	Dec 25

Some of the full-moon days have special significance in the Buddhist calendar:

• Magha Puja (February 19, 2000) -- "Sangha Day".
  This commemorates the spontaneous assembly of 1,250 arahants in the Buddha's presence. One thousand of the gathered monks had previously achieved Awakening upon hearing the Buddha's delivery of the Fire Sermon; the remaining 250 were followers of the elder monks Ven. Moggallana and Ven. Sariputta. To mark this auspicious gathering, the Buddha delivered the Ovada-Patimokkha Gatha, or Patimokkha Exhortation -- a summary of the main points of the Dhamma -- which the Buddha gave to the assembly before sending them out to proclaim the doctrine.

• Visakha Puja (Vesak) (May 17, 2000) -- "Buddha Day".
  This day commemorates three events in the Buddha's life that each took place on this full-moon day: his birth, Awakening, and final Unbinding (parinibbana).

• Asalha Puja (July 16, 2000) -- "Dhamma Day".
  This commemorates the Buddha's first discourse, which he gave to the group of five monks with whom he had practiced in the forest for many years. Upon hearing this discourse, one of the monks -- Ven. Kondañña -- gained his first glimpse of Nibbana, thus giving birth to the Noble Sangha. The annual Rains retreat (vassa) commences the following day.

• Pavarana Day (October 13, 2000).
  This day marks the conclusion of the Rains retreat (vassa). In the following month, the kathina ceremony is held, during which the laity gather to make formal offerings of robe cloth and other requisites to the Sangha.

• Anapanasati Day (November 11, 2000).
  At the end of one rains retreat (vassa), the Buddha was so pleased with the progress of the assembled monks that he encouraged them to extend their retreat for yet another month. On the full-moon day marking the end of that fourth month of retreat, he presented his now-famous instructions on mindfulness of breathing (anapanasati), which may be found in the Anapanasati Sutta (MN 118) -- The Discourse on Mindfulness of Breathing.

See also:

• Muluposatha Sutta (AN III.70) -- Discourse on the Roots of the Uposatha
• Uposatha Sutta (AN VIII.41) -- Discourse on the Uposatha Observance
• Visakhuposatha Sutta (AN VIII.43) -- Discourse to Visakha on the Uposatha
• Ñanavara Thera's Questions-and-answers concerning the Uposatha.
• Lay Buddhist Practice, by Bhikkhu Khantipalo (BPS Wheel Publication No. 206).
• "Visakha Puja," by Ajaan Lee.