Mahina, the moon, was the goddess who kept time for the Hawaiian. Mahina was more important to everyday life than the sun or the stars.
It was the duty of certain priests trained as astronomers to keep the annual calendar and watch the moon to determine just when certain tabu should be placed on the fish or land.
A proper planting season for the farmer depended upon the time as announced by the astronomer. The bird catcher, the canoe builder and many other craftsmen depended upon the astronomer’s announcement of the correct Mahina. (Taylor)
The Kilokilo (observer of the sly for omens) was an important person generally attached to the court of a king or to the temple of the king’s high priest. He was an astronomer priest, versed in the language of the stars.
The rising and the setting of the moon marked a day for the Hawaiian, only he did not call the time a day, he called it a night. The appearance of the new moon and the death of the old moon marked the month for the Hawaiian, which he called Mahina. Twelve such moons made a year for him.
The importance of knowing the passing of a year was to know when to celebrate the Makahiki, the great harvest festival. It was important to know just when the festival should be celebrated because it coincided with the coming of the god Lono on a visit to each district in the Islands. (Taylor)
The Hawaiian divided his calendar into the space of a year composed of 12 months or moons. He did not control the division of time known as a year by the sun, as we do, but by a small group of stars which we call the Pleiades and he called Makalii (small eyes).
There are many bright and beautiful stars with whom the Hawaiian was familiar and by which he might have regulated his calendar. Instead, he chose to regulate it by the rising and setting of this small constellation of seven stars. As a result, he considered the Pleiades the most important stars in the heavens.
Just why the Pleiades were selected as the regulator of the year is lost in antiquity. Most Asiatic, all the Pacific Island peoples and some Indian tribes use the rising and setting of the Pleiades as the regulator of the year.
The “Small Eyes” are to be seen on the eastern horizon about the middle of November each year. They travel across the sky for six months on the Black Shining Road of Kane and set about the middle of June in a pit located in the western sky. (Taylor)
In attempting to keep an ancient moon calendar, it is essential to know when to correct the moon calendar so that the seasons will correspond with the sun. That is the secret of the ancient astronomer which we do not know.
King Kalakaua said the astronomer corrected his calendar by adding five bonus days at the end of the Makahiki each year. Other old Hawaiians say that the astronomer simply knew when to add extra days or an extra month. (Taylor)
It is evident from the various accounts of the naming of the months of the year that the same names occurred in the various islands but that they were not applied to the same months. (Handy, Handy & Pukui)
Traditional month names are Ka‘elo, Kaulua, Nana, Welo, Ikiiki, Ka‘aona, Hina‘ia‘ele‘ele, Mahoe Mua, Mahoe Hope, Ikua, Welehu and Makali‘i.
The names of the months varied on each Island and within moku (districts) on each island, a result of the different methods the astronomer priest used to calculate days and months.
Apparently, astronomers on the different Islands and in the different districts had various methods of adjusting the calendar because we know that the names of the months varied on each Island. (Taylor)
The months of the pre-contact Hawaiian were lunar months, each beginning with the appearance of a new moon and lasting 29 or 30 nights until the appearance of the next new moon. Each night of the month had its individual name.
All authorities seem to agree that there were 12 named months. However, there is considerable disagreement as to their names, some disagreement as to their sequence, and evidence that the nomenclature both varied from island to island and was subject to change with time. (Schmitt & Cox)
Hawaiians divided the year into two seasons: Ka‘u, or Summer, when it was dry and hot (beginning in May when the Pleiades set at sunrise). The other part of the year was Ho‘oilo (beginning in October), when it was rainy and chilly. (Handy, Hany & Pukui) There were six months in Ka‘u and six in Ho‘oilo.
While most authorities agree that the months were grouped into two seasons, there is considerable disagreement as to the names of the seasons and the details of the grouping. Some, moreover, report three or four seasons. (Schmitt & Cox)
The lunar cycle was reconciled with the sidereal year (of or relating to stars or constellations) by the insertion of an extra month about once in three years.
The passage of sidereal was noted by the date on which the Pleiades were seen to rise just after sunset. However, the exact rule governing the insertion of the extra month, the point of its insertion in the sequence of the 12 named months, and the name given to the extra month have, apparently, all been forgotten. (Schmitt & Cox)
(Check out the attached images that further explain the names, what actions happen during certain months and some of the differences in names assigned to the calendar names we are used to (January through December).