What Is Yi Peng? The Meaning Behind Chiang Mai's Sky Lantern Festival

What Is Yi Peng?

Yi Peng (ยี่เป็ง) is the traditional lantern festival of Northern Thailand, celebrated by releasing hundreds of thousands of glowing sky lanterns, known as khom loi, into the night sky. Rooted in the ancient Lanna Kingdom, it takes place on the full moon of the twelfth month of the Lanna lunar calendar and is held alongside Loy Krathong, making Chiang Mai the most famous place in the world to witness it.

What Does "Yi Peng" Mean?

The name comes from the Lanna (Northern Thai) language: "Yi" means two, and "Peng" means full moon day. Together, Yi Peng refers to the full moon day of the second month according to the old Lanna lunar calendar, which runs about two months ahead of the standard Thai lunar calendar used in the rest of the country.

Because of this calendar difference, the "second month full moon" of Lanna reckoning lines up with the twelfth month of the national Thai calendar, which is the same night as Loy Krathong. That is why the two festivals always fall on the same dates, even though they come from different naming traditions.

The History of Yi Peng

Yi Peng's origins trace back centuries to the Lanna Kingdom, the northern Thai kingdom centred on Chiang Mai before it became part of Siam. In Lanna belief, releasing a khom loi is an act of merit connected to the legend of Phra Kesa Kaew Chulamani, a sacred chedi believed to enshrine a relic of the Buddha in the Tavatimsa heaven. Sending a lantern skyward is a way of paying homage to this relic and to the Buddha himself.

Over time, the tradition grew to also represent letting go of hardship and misfortune from the past year and opening the way for good fortune, much as Loy Krathong on the ground represents washing away bad luck by releasing a krathong onto the water. Today, Yi Peng and Loy Krathong are inseparable in Chiang Mai, celebrated together as one of the most visually spectacular festivals in Southeast Asia.

Historically, the festival was closely tied to specific temple communities around Chiang Mai, with districts such as Sansai becoming particularly well known for their own large-scale lantern releases at local temples. Monks would lead merit-making ceremonies before the lanterns were lit, and entire villages would gather to release them together, turning the night sky above the rice fields into a moving river of light. That communal, ceremonial spirit is still the model that organised festivals aim to recreate today.

Yi Peng vs Loy Krathong — What's the Difference?

The Three Lights of Yi Peng

Lanna tradition actually recognises three distinct forms of light offered during the festival, each with its own purpose:

• Khom loi — the sky lantern, released into the air as an offering that rises toward the heavens.
• Krathong — the decorated basket floated on water, representing the Loy Krathong side of the celebration.
• Phang pratip — small lit lamps or candles placed around homes, temples, and along streets to illuminate the community during the festival nights.

How Is a Khom Loi Made?

A khom loi is deceptively simple. A thin, heat-resistant paper — traditionally rice paper — is stretched over a light bamboo or wire ring to form a tall, hollow cylinder closed at the top. At the open base sits a fuel cell, usually a wax-and-fibre wick. Once lit, the flame heats the trapped air inside the paper shell, and just like a miniature hot-air balloon, the lantern becomes buoyant enough to lift off and drift upward on the night breeze, glowing until the fuel burns out.

What Do the Lanterns Symbolise?

Releasing a khom loi during Yi Peng carries several layers of meaning:

• Letting go of misfortune, worries, and negativity from the past year
• Making a wish for happiness, health, and prosperity
• Paying homage to and worshipping the Buddha
• Marking a fresh start and a new beginning

Many visitors take a quiet moment before the release to write a wish or a short prayer on the lantern's paper shell, then watch it drift upward with hundreds of others until the sky itself seems to shimmer. It is this combination of a personal, reflective act and a shared, collective spectacle that makes Yi Peng feel different from an ordinary fireworks show or light display — it is a ritual as much as it is a view.

When Is Yi Peng 2026?

Yi Peng 2026 falls on 24–25 November 2026, the full moon of the twelfth lunar month, celebrated together with Loy Krathong.

Because the date follows the lunar calendar, it shifts from year to year on the Western calendar:

Dates follow the full moon of the twelfth lunar month and are confirmed closer to each year; 2027 and 2028 are estimates.

How to Experience Yi Peng Today

Releasing sky lanterns inside Chiang Mai's city limits is no longer permitted. The volume of lanterns once released citywide became a safety hazard for air traffic in and out of Chiang Mai International Airport, and loose lanterns posed a fire risk to the old city's wooden temples and buildings. As a result, unauthorised releases within the city now carry heavy penalties.

To take part legally and safely today, visitors join an organised festival held in a permitted, open area outside the city, where mass lantern releases are coordinated with local authorities and aviation safety in mind. These events also bring back the cultural elements that make Yi Peng special: Lanna performances, Northern Thai food, and a real sense of community around the shared release.

In practice, this means a fixed program for the night: guests arrive while it is still light, enjoy dinner and traditional shows, and are guided through a short safety briefing before everyone lights and releases their lanterns together at a set time. Releasing as one large group, rather than individually and at will, is precisely what keeps the release both legal and safe — and it is also what produces the iconic wide-sky photographs the festival is famous for.