Religious Calendars & the Environment

Religions adopt different types of annual calendars: solar, lunar, and lunisolar. A solar calendar has months that correspond to the season or the apparent position of the sun in relation to the stars. A lunar calendar has months that correspond to cycles of moon phases. A lunisolar calendar has lunar months that are brought into alignment with the solar year through periodic adjustment.

The solar calendar, such as followed by Christians, has 12 months, each containing 30 or 31 days, taking up the astronomical slack with 28 or 29 days in February. Islam uses a lunar calendar, which has around 354 days. The Jewish calendar is lunisolar, with most years comprising around 354 days, but adding a thirteenth month every two or three years to line up with agricultural and solar calendars.

Regardless of the type that is used, the annual calendar of a religion typically includes holidays with theological themes. In universalizing religions, major holidays often relate to events in the life of the founder. A prominent feature of ethnic religions is the idea that adherents have a shared history, language, and destiny, and the calendar and holidays often refer to this shared history. An ethnic religion may also refer to distinctive physical geography such as celebration of the seasons—the calendar’s annual cycle of variation in climatic conditions. Rituals may be performed to pray for favorable environmental conditions or to give thanks for past success.

The Calendar in Several Religions

The principal purpose of the holidays in universalizing religions is to commemorate events in the founder’s life. Examples can be found in the various universalizing religions.

Islam

Islam uses a lunar calendar. In a 30-year cycle, the Islamic calendar has 19 years with 354 days and 11 years with 355 days. As a result, Islamic holidays arrive in different seasons from generation to generation.

The start of Ramadan, during which Muslims fast from sunup to sundown, has in recent years occurred in the Northern Hemisphere spring—for example, April 23, 2020, on the western Gregorian calendar. In 2010, Ramadan started in the Northern Hemisphere summer on August 11, and in 2030 Ramadan will start in the winter on January 5. Because Ramadan occurs at different times of the solar year in different generations, the number of hours of the daily fast varies widely because the amount of daylight varies by season and by location on Earth’s surface.

Observance of Ramadan can be a hardship because it can interfere with critical agricultural activities, depending on the season. However, as a universalizing religion with 1.9 billion adherents worldwide, Islam is practiced in various climates and latitudes. If Ramadan were fixed to correspond with the agricultural cycle in Southwest Asia, it would not match the cultivation and harvest times for Muslims elsewhere in the world.

Christianity

Christians commemorate the resurrection of Jesus on Easter, observed on the first Sunday after the first full Moon following the spring equinox in late March. But not all Christians observe Easter on the same day because Protestant and Roman Catholic branches calculate the date on the Gregorian calendar, whereas Orthodox churches use the Julian calendar.

Christians associate their holidays with seasonal variations in the calendar, but climate and the agricultural cycle are not central to the liturgy and rituals. In Southern Europe, Easter is a joyous time of harvest. Northern Europe and North America do not have a major Christian holiday at harvest time, which would be placed in the fall.

Most Northern Europeans and North Americans associate Christmas, the birthday of Jesus, with winter conditions, such as low temperatures, snow cover, and the absence of vegetation except for needle-leaf evergreens. But for Christians in the Southern Hemisphere, December 25 is the height of summer, with warm days and abundant sunlight.

Buddhism

All Buddhists celebrate as major holidays Buddha’s birth, Enlightenment, and death. However, not all Buddhists observe them on the same days. Theravadist Buddhists observe all three events on the same day, usually in May. However, some Buddhists observe them on different days.

Sikhism

The major holidays in Sikhism are the births and deaths of the religion’s 10 gurus. The tenth guru, Gobind Singh, declared that after his death, instead of an eleventh guru, Sikhism’s highest spiritual authority would be the holy scriptures the Guru Granth Sahib. The most important holidays in Sikhism are festivals marking the birthday or martyrdom of a guru. Commemorating historical events distinguishes Sikhism as a universalizing religion, in contrast to India’s major ethnic religion, Hinduism, which glorifies the physical geography of India.

Bahá'í

The Bahá'ís use a calendar established by the Báb and confirmed by Bahá'u'lláh, in which the year is divided into 19 months of 19 days each, with the addition of four extra days (five in leap years). The year begins on the first day of spring, March 21, one of several holy days in the Bahá'í calendar. Bahá'ís attend the Nineteen Day Feast, held on the first day of each month of the Bahá'í calendar, to pray, read scriptures, and discuss community activities.

Pause & Reflect 6.3.6

Why do some religions organize their annual calendars according to the lunar or lunisolar cycle?

The Calendar in Judaism

Judaism’s three major holidays are based on events in the Hebrew Bible and connected to the agricultural calendar of the religion’s homeland in present-day Israel. These holidays are known as pilgrimage festivals, because the Torah called for the Israelites to come to the Temple in Jerusalem. Following the destruction of the Second Temple, observance of these festivals shifted, though Jews in Israel often try to attend prayer services at the Western Wall (the remaining accessible part of the Second Temple).

Major Jewish holidays include:

• Pesach (Passover) celebrates the liberation of the Jews from slavery in Egypt to freedom and the time for harvesting barley in the land of Israel.

• Shavuot (Feast of Weeks), which falls exactly seven weeks after Pesach, comes at the time for harvesting wheat. It is also considered the date when Moses received the Torah from God.

• Sukkot recalls the period of 40 years when the Israelites were in the desert and relied on God for food and shelter. The term derives from the Hebrew word for the “booths,” or “temporary shelters,” which the Israelites used in the desert. Sukkot also celebrates the final harvest of the year. Prayers, especially for rain, are offered to bring success to the upcoming agricultural year

Holidays in Judaism

Jews bless the etrog (citron) and lulav (date palm branches) during the holiday of Sukkot at a synagogue in Brooklyn, New York.

Rosh Hashanah (New Year) and Yom Kippur (Day of Atonement), the two most holy and solemn observances in the Jewish calendar, come in the autumn. Rosh Hashanah marks the beginning of the Ten Days of Repentance that conclude on Yom Kippur.

The Solstice

The solstice has special significance in some ethnic religions. A major holiday in some pagan religions is the winter solstice, December 21 or 22 in the Northern Hemisphere. The winter solstice is the shortest day and longest night of the year, when the Sun appears lowest in the sky, and the apparent movement of the Sun’s path north or south comes to a stop before reversing direction (solstice comes from the Latin to “stand still”). Stonehenge, a collection of stones erected in southwestern England some 4,500 years ago, is a prominent remnant of a pagan structure apparently aligned so that the Sun rises directly between two stones on the summer and winter solstices.

Stonehenge

The 30 enormous stones that comprise Stonehenge were erected around 4,500 years ago. The stones replaced earlier circular arrangements made originally of timber, probably around 5,000 years ago.