Why Does Hot Weather Make People More Irritable?

JAKARTA — Hot weather and drier air continued to affect several parts of Indonesia in early October 2026. The Meteorology, Climatology and Geophysics Agency (BMKG) said the conditions were occurring amid a very strong El Niño and a positive phase of the Indian Ocean Dipole (IOD).

Relatively dry atmospheric conditions affect not only the environment but can also make the body tire more quickly and influence emotional wellbeing. Alifah Nabilah Masturah, a psychologist at the University of Muhammadiyah Malang (UMM), said discomfort caused by high temperatures can place a burden on the body, both physically and psychologically.

In psychology, this is linked to stimulus-load theory, in which the body receives environmental stimulation that exceeds its normal capacity. “If the stimuli we receive, or the conditions we experience, exceed the body’s normal capacity, this will lead to an increase in the hormone cortisol. Cortisol is one of the triggers of stress,” Alifah said in a written statement, quoted on Monday (12 October 2026).

Alifah said increased stress caused by uncomfortable environmental conditions can affect emotional responses. High temperatures make the body work harder to adapt, increasing fatigue and discomfort. They can also prevent thinking processes from working optimally.

As a result, people may become more sensitive to other people’s words and actions. Things that are actually neutral may more easily be interpreted as annoying or negative.

“Neutral things might be perceived as a loud voice, [or make us think], ‘Why are they being so snappy?’ Or someone is joking, but it sounds rather rude,” Alifah said.

Alongside ambient temperature, a person’s physical condition also influences their ability to manage emotions. Dehydration and lack of sleep can worsen physical health and affect psychological wellbeing. Maintaining the body’s condition is therefore important in anticipating mood changes during hot weather.

Sleep quality is one factor that needs attention. Alifah stressed that good sleep is measured not only by its duration, but also by how effectively the body and brain are able to rest. “Sleep is not about how long it lasts, but its quality,” she said.