The heat index in Bangkok is in the danger zone, with “feels like” temperatures on Thursday ranging between 42 and 51.9 degrees Celsius, City Hall has warned.

Official maximum temperatures in the capital are forecast to range between 34C and 39C over the next few days, according to the Meteorological Department. But anyone who has to spend much time outdoors will feel a lot hotter.

The heat index refers to the temperature the human body actually feels. It depends on both the air temperature and relative humidity, and it is more suitable for indicating the risk of heat‑related health impacts than using only the maximum temperature.

The heat index can be divided into four levels:

•     27.0 – 32.9C: Caution
•     33.0 – 41.9C: Warning
•     42.0 – 51.9C: Danger
•     Above 52C: Extreme Danger.

Risk groups include young children aged up to 5 years old, the elderly aged 60 or older, pregnant women, patients with chronic diseases, individuals with obesity, people who consume alcohol, outdoor workers, those who exercise outdoors and tourists. 

Health impacts could include fatigue, dizziness, rashes, redness or swelling, muscle cramps and heat stroke, which could be fatal.