While most of the world agrees that the new year begins on January 1, in Southeast Asia the answer is far less straightforward. Thailand celebrates its new year in April through Songkran, while Bali shuts down its international airport for a full 24 hours to mark the Saka New Year.
Several ancient calendar systems in the region have survived not as museum relics, but as living frameworks that still determine when people marry, when markets operate, and even when airplanes are not allowed to fly. These are some of the calendars that remain actively used today.
1. Hijri Calendar
The Hijri calendar is based on the lunar cycle, meaning a Hijri year lasts only 354 days, or about 11 days shorter than the Gregorian year. As a result, Ramadan shifts around 11 days earlier each year, and a single Gregorian year can contain two Hijri years at once. In 2025, for example, both 1446 and 1447 AH fall within the same year.
In Indonesia, Malaysia, and Brunei, the calendar is actively used to determine the beginning of Ramadan, Eid al-Fitr, Eid al-Adha, and the Hajj schedule. The dates are not always synchronized across countries because different methods are used: some rely on rukyat, or direct moon sighting, while others use hisab, or astronomical calculations.
These differences sometimes cause neighboring countries to celebrate Eid on different dates.
2. Javanese Calendar
Created by Sultan Agung of Mataram in 1633, the Javanese calendar combines the Hindu-Saka system with the Islamic Hijri calendar. Its most distinctive feature is the pasaran cycle, a repeating five-day cycle (Legi, Pahing, Pon, Wage, and Kliwon) that runs alongside the standard seven-day week.
The combination of both produces the weton, a person’s birth-day marker as well as a form of spiritual guidance.
To this day, weton remains an important consideration among Javanese communities before deciding wedding dates, moving houses, or starting a business. Beyond cultural traditions, the pasaran cycle is also still used to organize traditional market schedules. Pasar Wage, for example, is busiest on Wage days.
3. Buddhist Era (BE) Calendar
Thailand uses a dual calendar system. For international affairs, it follows the Gregorian calendar. However, for domestic official documents such as driver’s licenses, passports, and government contracts, the Thai solar calendar is used with Buddhist Era numbering, which adds 543 years to the Gregorian year. As a result, 2025 CE is recorded as 2568 BE in Thailand.
At the same time, the traditional lunisolar calendar continues to be used in parallel to determine major Theravada Buddhist holidays such as Vesak and Asalha Puja, whose dates follow lunar phases and shift every year. Myanmar, Cambodia, and Laos use systems rooted in the same tradition.
4. Balinese Saka Calendar
The Balinese Saka calendar is lunisolar, combining both solar and lunar calculations. The system has been in use since around the first century CE and serves as the basis for determining all major Hindu ceremonies in Bali, from Galungan to Kuningan. Because it follows the lunar cycle, these dates shift every year when aligned with the Gregorian calendar.
Its most visible impact is during Nyepi, the Saka New Year, which falls on March 29 in 2025 and March 19 in 2026. For a full 24 hours, all activity across Bali comes to a complete stop: no vehicles, no lights, and no flights.
Ngurah Rai International Airport shuts down entirely, and the restrictions apply to everyone on the island, including tourists.
5. Chinese Lunar Calendar
The traditional Chinese calendar is lunar-based, with the new year falling between late January and mid-February depending on the moon cycle. Each year is named after one of the 12 zodiac animals within a 60-year cycle. The year 2025, for example, is the Year of the Snake, beginning on January 29.
The calendar is still actively used among Chinese communities in Singapore, Malaysia, Vietnam, and Thailand to determine auspicious dates for weddings, house construction, and business openings. In Vietnam, Tết Nguyên Đán, which follows this calendar rather than January 1, marks the largest annual human migration in the country.
