
Yoruba calendar

The Yoruba calendar ("Kojoda") is a calendar used by the Yoruba people of southwestern and north central Nigeria and southern Benin. The calendar has a year beginning on the last moon of May or first moon of June of the Gregorian calendar. The new year coincides with the Ifá festival.
The traditional Yoruba week has four days. The four days that are dedicated to the Orisa go as follow:
To reconcile with the Gregorian calendar, Yoruba people also measure time in seven days a week and four weeks a month. The four-day calendar was dedicated to the Orisas and the seven-day calendar is for doing business.
The seven days are: Ọjọ́-Aiku (Sunday), Ọjọ́-Aje (Monday), O̩jọ́-Iṣẹgun (Tuesday), Ojo-Irú (Wednesday), Ọjọ́-Bo̩ (Thursday), Ọjọ́-E̩tì (Friday) and O̩jọ́-Àbamé̩ta (Saturday).
Time is measured in iseju aaya (seconds), iṣeju (minutes), wakati (hours), ọjọ́ (days), o̩sẹ̀ (weeks), oṣu (months) and o̩dun (years). There are 60 (ogota) iseju aaya in 1 (ookan) iseju (minute); 60 (ọgọta) iṣẹju in 1 (ookan) wakati; 24 (merinlelogun) wakati (hours) in 1 ọjọ́ (day); 7 (meje) ọjọ́ (days) in 1 ọsẹ̀ (week); 4 (mẹrin) ọsẹ̀ (weeks) in 1 oṣu (month) and 52 (mejilelaado̩ta) ọsẹ̀ (weeks) in 1 (ookan) o̩dun (year).
There are 12 (mejila) oṣù (month) in 1 (ookan) ọdun (year).
Calendar examples.
“KỌ́JỌ́DÁ” - 'Ki ọjó̩ dá: may the day be clear(ly foreseen), calendar'.
The traditional Yoruba calendar (Kọ́jọ́da) has a 4-day week and 91 weeks in a year.
The Yoruba year spans from 3 June of a Gregorian calendar year to 2 June of the following year. 
According to the calendar developed by Remi-Niyi Alaran, the Gregorian year AD is the year of Yoruba records of time. With the British colonial and European cultural invasions, came the need to reconcile with the Gregorian calendar: Yoruba people also measure time in seven days a week and 52 weeks a year. 
The year in festivals.
Note: since there are thirteen months in the Youruba calendar, the relation between the Gregorian and Yoruban months is approximate only.
Ajȯdun Yoruba
Sere/ January.
Obatala
Erele / February.
Olokún = Oríṣà of Okún, the deep seas or oceans, patron of sailors, and guardian of souls lost at sea.
Erele/Feb 21-25
Erénà / March.
Annual rites of passage for men
Èrèna/March 12 – 28
Oduduwa (odudu, the dark pigment; ni ewa, is the beauty) / Iyaagbe (iya, mother; agbe, who receives) = Oríṣà of Earth and matron of the Ayé. Oduduwa endows the ebony dark skin pigment that accords greatest gifts of spirituality, beauty and intellect to the bearer. The essence of procreative love.
Èrèna/March 15 – 19
Oshosi = Oríṣà of Adventure and the hunt 
Èrèna/March 21 – 24:
Igbe / April.
Onset of wet season (Spring)
Èbìbí / May.
Egungun (Commemoration of the Ancestors, including community founders and illustrious dead.
Èbíbí: starts last Saturday of May, for 7 days
Agẹmo / July.
Agẹmo: first and second weeks in July
Oko (Agriculture) Harvesting of the new Yam crop.
Ẹlégba-Bara (Ẹlégba, one who has power to seize) / Eṣu (shu, to release eject from; ara, the body) = Oríṣà of male essence and Power, who is the great Communicator and messenger of the will of Olódùmarè. No woman should bara (ba ra, to rub with, have intercourse with) a man who has not done Ikola (circumcision: ike, cutting; ola, that saves) in sacrifice to Ẹlégba. 
Agẹmo second weekend of July
Ṣàngo (shan, to strike:/ Jakuta:ja, fight; pẹlu okuta, with stones). The Oríṣà of Energy – Ara (Thunder) and Manamana, make lightning, whose divination is with 16 cowries and whose messenger and water-bearer is Oshumare (the Rainbow).
Agẹmo: third week of July
Ogun / August.
Oṣun-Oṣogbo
Oṣun = Oríṣà of Fertility and custodian of the female essence. who guides pregnancies to term. 
Ogun: last weekend of August
Ogun = Oríṣà of fire, iron/metals (i.e. - a smith), war crafts, technology and engineering. The custodian of truth and executioner of justice, as such patron of the legal and counselling professions who must swear to uphold truth while biting on a piece of metal.
Òwéwé / September.
It is the month in which festivals are being celebrated and a month of blessing. It celebrates how Yoruba is a rich culture.
Ọwara / October.
Oya (Orísà of the odo Oya (river Niger) whose messenger is Afefe (the Wind), and guardian of gateway between the physical realm (Aye) and the spiritual realm (Òrún).
Ọwaro
Ọwaro third weekend of October
Onset of the dry season (Autumn)
Shigidi (Orísà of Òrún-Apadi, the realm of the unsettled spirits and the ghosts of the dead that have left Aye and are forsaken of Òrún-Rere. Custodian of nightmares and patron of assassins.
Solemn candlelight to guide the unsettled away from your residence, else they settle in your dolls or other toys.
Bèlu / November.
ÒPE/ December===
Obaluaye (Oríṣà of Ṣòwò (Commerce) and owo (wealth).
Òpé 15
Onset of the second dry season (winter solstice)