In Southeast Asia, some countries posted their highest ever recorded temperatures this week, while searing heat in the Indian subcontinent has killed more than a dozen people.

Laos is the latest country to set a new all-time record as Luang Prabang reached 42.7°C (109°F) Tuesday, according to weather historian Maximiliano Herrera.

Over the weekend, Thailand topped 45°C (113°F) for the first time in its history, according to Herrera, using data from the Thai Meteorological Department. The northwest city of Tak reached 45.4°C Saturday, but large portions of the country have been in the upper 30s to low 40s since late March.

Earlier this month, Thai authorities issued a health alert for several provinces as the heat index was forecast to reach 50.2°C in the Bang Na district of the capital Bangkok. The heat index is what the temperature “feels like” and considers both air temperature and humidity to measure its impact.

On Tuesday, Thai Prime Minister Prayut Chan-o-cha expressed concern over “dangerously high temperatures in various parts of Thailand” and said in Bangkok’s Bang Na area, temperatures “could reach 52.3°C,” according to a statement from the prime ministers office.

Neighboring Myanmar set an April temperature record on Monday as Kalewa, in central Sagaing region, reached 44°C (111°F), Herrera tweeted.

April and May are typically the hottest months of the year for South and Southeast Asia as temperatures rise before monsoon rains begin and bring some relief.

But the heat in Thailand has been compounded by an intense smoggy season that has caused pollution levels to spike.

The tourist hotspot of Chiang Mai in the north ranked as the world’s most polluted city for seven straight days as smoke from forest fires and widespread crop burning deteriorated the air quality. At least one hospital in the city said it had reached “full ward capacity” as patients sought medical treatment for respiratory issues.

The scorching temperatures have also been widespread across China.

On Tuesday, the country saw temperatures as high as 42.4°C (108°F) in Yuanyang, in the southeast – only 0.3°C from the country-wide record for April, according to Herrera.

On Monday, more than 100 weather stations in 12 provinces broke their April temperature record, according to climatologist Jim Yang.

Although not record-breaking in most cases, the heat has also been prevalent – and deadly – across South Asia. Pakistan, India, Nepal and Bangladesh have all seen temperatures topping 40°C (104°F) for many days.

According to India’s Meteorological Department, 48 weather stations recorded temperatures over 42°C on Tuesday, with the highest at 44.2°C in the eastern state of Odisha.

In western Maharashtra state, at least 13 people died from heatstroke after attending a state award ceremony on Sunday. More than 1 million people attended the event in Navi Mumbai and between 50 to 60 people were hospitalized, according to a city police official.

Meanwhile, at least two states, Tripura in the northeast and West Bengal in the east, ordered schools to shut this week, as temperatures rose more than 5 degrees Celsius above normal, state governments said, Reuters reported.

The Indian Ministry of Labor issued an advisory to all states and regions to ensure the safety of workers – especially outdoor laborers and miners – in the extreme heat. That includes providing adequate drinking water, emergency ice packs, and frequent rest breaks.

Heat waves in India usually take place between March and July, but in recent years these hot spells have become more intense, more frequent and longer.

Last year, India experienced a searing heatwave, where parts of the country reached more than 49°C (120°F). As the impacts of the human-caused climate crisis accelerate and global temperatures continue to rise, scientists say heat waves will only become more common.

A 2022 study found that dangerous heat waves will be between three and 10 times more often by the turn of the century.

In the tropics, which encompasses much of Asia, people could be exposed to dangerous heat most days of the year, the study found. Days of “extremely dangerous heat” – which is defined as 51°C (124°F) – could double and experts say those levels of heat push the limits of human survivability.

Extremely hot temperatures across South and Southeast Asia are expected to continue. Meanwhile, cooler conditions are on the way for much of China as temperatures are forecast to fall from around 10°C (18°F) above average to 10°C (18° F) below average this weekend.