Southeast Asia’s Burning Season: What You Need to Know

One of the things we are most often asked about here at South East Asia Backpacker is the so-called ‘burning season’ or ‘smoky season’ of Southeast Asia. Travellers often ask two questions…

1. Is the burning season really that bad?
2. Is it worth altering my travel plans to avoid the burning season?

Having experienced this time of year first-hand several times, my answer to both questions is YES. It is really that bad, and YES you should consider rescheduling your trip. Read on to find out why.

Related: (opens in new tab)

• 🗓️ Southeast Asia Climate Planner
• ☔️ Monsoon Season in Southeast Asia
• 🍌 Classic Southeast Asia Itinerary

A Guide to The Burning Season in Southeast Asia

What is the Burning Season? 🔥

The burning season, or ‘haze’ as it is sometimes referred to, is mainly caused by local farmers burning old crops in the fields or burning patches of forest land to make way for new planting. This is known as slash and burn farming or agriculture. This method is centuries old, but in a modern world where the climate (and the start of the rainy season) is becoming more and more unpredictable, it is causing an immense amount of air pollution, which lingers around for months on end.

In addition to the smoke emitted from the fields, there is also the exhaust fumes of thousands of cars and motorbikes as well as smoke/dust from factories and small ‘trash fires’ added to the toxic mix.

There is also the issue of ‘forest clearances’ where enormous areas of ancient rainforest are burnt to make way for the planting of palm oil trees, one of the planet’s most lucrative, but destructive, products. This is most common in Indonesia where it is suggested that over 2.4 million hectares of rainforest are destroyed each year. This not only causes air pollution problems but destroys the habitat for thousands of indigenous species, not to mention the homes of tribal peoples who live in the forest.

Where Does the Burning Season Affect? 🗺️

Northern Thailand and Northern Laos – March/April

The burning season affects all of Northern Thailand (Chiang Mai, Pai, Mae Hong Son, Chiang Dao, Chiang Rai, Phayao, Nan etc.) and Northern Laos (Luang Prabang, Vang Vieng, Luang Namtha and Nong Khiaw).

The city of Chiang Mai is particularly badly affected, with the Air Quality Index (AQI) hitting horrendous levels on a regular basis. Due to the placement of the city in a valley where the haze tends to linger, as well as the pollution from the city’s traffic, Chiang Mai often tops the list of places with the worst air quality in the world. In recent years, local government have been taking measures to tackle the problem and clean up the skies over Chiang Mai.

Malaysia and Indonesia – September/October

There is also a burning season which occurs in Malaysia and Indonesia during their dry season and peaking in September/October mainly caused by forest fires in Sumatra and Indonesian Borneo (Kalimantan). The haze affects west Indonesia, especially Sumatra and Borneo, as well as all of Peninsular Malaysia, particularly cities like Georgetown in Penang, the capital Kuala Lumpur, as well as Singapore.

When is the Burning Season Exactly? 🗓️

It is important to realise that there is no official start date to the burning season and it is impossible to predict exactly when it will begin and end. Every year is different and some years are much worse than others. 2015 was one of the worst years on record, and 2019 was also particularly severe when a state of emergency was declared in Thailand.

In the North of Thailand and Laos

The worst of the burning season usually occurs mid-March to mid-April. This coincides with the hottest time of year in Thailand and Laos making the atmosphere even more unpleasant. 

In days gone by, when the start of the rainy season was more predictable, the monsoon rains would arrive at the end of April and clean the air of any smoke. (The water festival Songkran, also known as the start of the Buddhist New Year, is historically a symbol for the start of the rainy season.)

However, nowadays with the rains coming later each year, the smoke can linger around much longer. In addition, as we’ve heard from travellers in our Facebook community, farmers are now starting to burn earlier than ever, which is very bad news for the air quality!

“They’re already burning around Northern Thailand [in January] and have been for about a week or so. This is around a month earlier than normal! Nothing is a ‘given’ in Thailand, travellers should be prepared to play things by ear, evaluate the situation as best they can… They’re meant to stop burning in April I believe, but it’s that time when the mushrooms appear, so a lot of illegal burning takes place as well as rubbish pit fires still smouldering for weeks, and wildfires starting everywhere, my best guess from discarded glass bottles… March/April I would avoid like the plague, though February and May can still be enjoyable in some places.” Guy Mitchell, South East Asia Backpacker Community Member

In Malaysia and Indonesia

The worst of the smoky season hits Malaysia and Indonesia at the beginning of September lasting until early October which coincides with their hot/dry season. Extreme levels of air pollution have even caused the closure of airports.

“I was planning to stay longer in Malaysia but due to the air quality I changed my plans. I knew about the burning season but would never imagine it was that bad!” South East Asia Backpacker Community Member

Elsewhere in Southeast Asia

The burning of fields occurs in Southeast Asia during the dry seasons, meaning that this can occur in various microclimates at any time.

The burning of rubbish in local homes is also a common practice across the whole of Asia that can cause dangerous air pollution at any time. Several NGOs are trying to warn locals of the dangers of burning their waste. We particularly like this video made by Trash Hero, an initiative that promotes community clean-ups and plastic waste reduction.

Read more about Southeast Asia’s climate.

Air Quality Index and Particulate Matter 💨

What is AQI?

Here comes the sciencey bit 🤓. AQI stands for Air Quality Index (sometimes referred to as API or Air Pollution Index) and is a method for measuring the air pollution levels across the world. It is intended as a guide to how healthy or unhealthy the air is in any given place on any given day. There are six different categories ranging from healthy to hazardous.

The AQI takes into account levels of particle pollution (particulate matter or PM, see below) as well as the level of carbon monoxide, nitrogen dioxide, sulphur dioxide and ground-level ozone in the atmosphere. An AQI below 100 is usually considered normal and fairly healthy.

During the burning season in Southeast Asia the AQI often lies in the ‘Very Unhealthy’ category with AQIs well over 200, at times reaching above 300. If you are travelling during the burning season it is important to check the AQI to decide if you should travel there. You can check the AQI for any city on earth here.

What is PM?

PM stands for particulate matter and is often discussed with relation to air pollution. The term is used to talk about how much solid and liquid particle matter is mixed into the air. Some particles such as dust and soot can be seen by the eye, however, some are too small to be seen and can be detected only with a microscope. The two smaller types of particle matter that are dangerous to human health are:

• PM10 – particles with diameters that are 10 micrometers and smaller.
• PM2.5 – particles that are 2.5 micrometers and smaller. 

The finest of particles (PM2.5) are the ones that cause the greatest risk to humans as they can be inhaled into your lungs and even your bloodstream and have been known to be a cause of disease and cancer. During the burning season both PM10 and PM2.5 particles are present.

FAQs About Burning Season

What Problems Can the Burning Season Cause?

The smoky season causes mild health problems to almost everyone that experiences it, such as burning eyes, itchy nose and sporadic coughing fits. However, those with respiratory problems or those who are immunosuppressed can be particularly affected. Poor air quality can cause diseases such as asthma and lung infections as well as trigger the development of more chronic illnesses such as lung disease and emphysema.

Activities such as hiking, cycling and general outdoor fun is practically impossible during this time as it is not advised to do any exercise in such poor-quality air. Organised treks have been known to be cancelled due to poor air quality. It’s also not uncommon for Thailand to shut down schools due to air pollution

Can I Protect Myself Against It?

In cities across Southeast Asia you will see many people wearing masks to protect themselves against the poor air quality. If you cannot change your travel plans and you will be travelling for only a short period in an area that is affected by the burning season it is wise to get yourself a mask before you arrive as they can be sold out in pharmacies during the worst times.

“I was there last year in Chiang Mai during ‘burning’ season. My advice is to bring with you N95 masks. Your clothes, your hair, the clothes you hang out to dry, even your backpack will smell as if it came out of a sooty chimney.” South East Asia Backpacker Community Member

Should I Rearrange My Trip?

So, when travellers ask me ‘Is it really that bad?’, having lived in Chiang Mai through the burning season, I can honestly say that yes, it really is that bad and I would recommend that you avoid it as much as possible. (I personally escaped during my first burning season and went to Kanchanaburi in Central Thailand for a few weeks until the air got better up North!)

In all honesty, the burning season is not a lot of fun and it is really not the best time to enjoy Southeast Asia. The smoke makes all outdoor activities (even walking) pretty unpleasant and if you want to engage in adventures such as hiking, biking, rafting and climbing, you really should consider rearranging your trip. 

Those with existing respiratory illnesses, families with small children or the elderly should definitely avoid travelling to affected areas during this time. For short visits or trips that cannot be rescheduled, buy yourself a good quality N95 face mask and engage in less strenuous and/or indoor activities like cooking classes, market visits and café hopping.

Where Can I Go Instead of Northern Thailand?

There are lots of other places to go! Central and South Thailand are not affected by smoke in the same way and are fine during the months of March and April. Check out our Thailand Travel Guide and Thailand Itinerary for alternative places to travel in Thailand during the burning season. Vietnam and Cambodia are also great at this time of year, as are Malaysia and Indonesia. See here for more information on seasons in Southeast Asia.

Have you travelled during the burning in Southeast Asia? Let us know about your experience in the comments!

Nikki Scott | Founder & Editor

Nikki is the founding editor of South East Asia Backpacker and The Backpacker Network. In her early twenties, she left her home in the North of England on a solo backpacking adventure and never returned! After six months on the road, she founded a print magazine that became legendary on the Banana Pancake Trail. The rest is history.

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