The Hawaiian moon calendar: the nights of the month

The Hawaiian moon calendar (kaulana mahina, 'positions of the moon') names every night (pō) of the lunar month (malama/mahina). The nights guided fishing, planting, ceremony and rest; it is still used today by fishpond keepers, farmers, voyagers and schools. Malo: 'There were thirty nights and days in each month; seventeen of these days had compound names and thirteen had simple names ... given to the different nights to correspond to the phases of the moon.'

Tonight in Hawaiʻi (Sunday 25 October 2026) is Hoku, night 15 of a month of 30 nights that began with Hilo on Sunday 11 October 2026. The next Hilo, the first crescent, is expected on Tuesday 10 November 2026.

How the nights are counted

The calendar is observational. Hilo is the night the new crescent is first seen in the west after sunset (Malo: 'The first appearance of the moon at evening in the west marked the first day of the month'). Emerson's note to Malo: 'the night of Hilo always had to coincide with the first appearance of the new moon in the west, and that of Akua or Hoku with the full moon.' Because the synodic month is 29.53 days, months alternate between 29 and 30 nights; in 29-night months one name is dropped (in modern printed calendars often Mauli). Practitioners today watch (kilo) the moon itself: a night begins when its moon rises, so 'if it rises as Kūkahi, then Kūlua doesn't start until Kūlua rises' (He'eia practitioner, Pacific Worlds). Three lunar months were intercalated in eight years to keep the months with the seasons (Emerson). For a website: start Hilo on the first evening the crescent is visible from Hawaiʻi (use a crescent-visibility criterion for ~20°N, 157°W, or simply the evening after the first sunset at which the moon is about 1-1.5 days old), count the nights from there, and check that Akua/Hoku falls on or next to the astronomical full moon; say clearly that the site's dates are calculated and that kilo (local observation) decides.

• Hoʻonui, 'growing bigger', the waxing moon: nights 1-10 (Hilo to ʻOlepau)
• Poepoe, 'round', the full moon: nights 11-20 (Huna to Lāʻaupau)
• Hoʻēmi, 'decreasing', the waning moon (also written Hāʻemi, ʻEmi): nights 21-30 (ʻOlekūkahi to Muku)

The nights of this month

What the nights are for

• Kū nights: good for fishing and for planting 'Kū plants', things that grow upright such as the coconut (He'eia practitioner).
• ʻOle ('nothing, not') nights: not for big projects, meetings or building; good for maintenance (mending nets, weeding, cleaning). Fishing is generally considered poor (He'eia practitioner; ʻole = not).
• Full-moon nights: productive, good for planting (fruit plants on Hua, 'fruitful'), for meetings with a good outcome and for procreation (He'eia practitioner).
• Lāʻau ('plant, tree, stick') nights: pole fishing (lāʻau = pole), harvesting and planting medicine and leafy crops (He'eia practitioner).
• Kāloa (Kanaloa) nights: associated with the deep ocean; especially good for fishing (Kaʻahele Hawaiʻi); planting vines that crawl and stretch (sweet potato, beans, squash) (He'eia practitioner).

Names, order and the number of nights differ between islands, districts and families. Kaʻahele Hawaiʻi compares five 19th-early 20th century calendars (Kalokuokamaile, Kepelino, Malo, newspaper sources) that all differ slightly; fishermen and farmers kept different versions; Malo himself notes that even on one island there was more than one nomenclature (for months). The waning ʻOle nights are three in Malo but four in some lists; 17 is Kulu or Kulua; Hoku is the 'fullest' moon for some, Akua for others. Month names differ even more between islands (e.g. Malo's Hawaiʻi Island list vs. Oʻahu/Kauaʻi lists). The Edith Kanakaʻole Foundation and the Office of Hawaiian Affairs publish modern calendars; Kalei Nuʻuhiwa is a leading present-day teacher of kaulana mahina.

Hilo is calculated as the first evening on which the new crescent can be seen from Honolulu (Odeh's criterion). It is an aid: those who keep the calendar watch the moon itself (kilo), and families and islands differ.