Reduced sunlight and high humidity during the rainy season can sap energy and dampen mood, but simple habits like bright lighting, exercise and ventilation can help.
Pedestrians carrying umbrellas walk across Gwanghwamun Square in central Seoul as monsoon rain falls on the morning of July 6. The Korea Meteorological Administration forecast continued rainfall across much of the country as the seasonal rain front moved northward.NEWS1
Han Seon-hwa
The author is an honorary professor at UST and former president of the Korea Institute of Science and Technology Information.
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This year's monsoon arrived a little later than usual. During the rainy season, sunlight becomes scarcer while humidity rises. These two environmental changes directly affect neurotransmitters in the brain.
Sunlight stimulates the production of serotonin, a chemical associated with happiness and emotional stability. When overcast skies persist for days, serotonin levels can decline, making people more prone to lethargy and low moods. High humidity also interferes with the body's ability to regulate temperature because sweat evaporates less efficiently. To maintain a stable body temperature, the body must continue producing sweat and increasing blood circulation, placing greater physiological demands on itself. As a result, people often feel tired more easily and have greater difficulty concentrating.
Feeling unusually fatigued or depressed during the monsoon is therefore not simply a matter of perception. Reduced sunlight and elevated humidity simultaneously alter brain chemistry and the body's physiological responses, producing measurable effects on both mood and energy.
The encouraging news is that while the brain responds to environmental changes, it also reacts when we make even modest adjustments to our surroundings. On cloudy days, keeping indoor lighting bright during daytime hours can help compensate for the lack of natural light. Even when it is raining, spending a short time outdoors to absorb available daylight may stimulate serotonin production.
Light exercise also increases the release of endorphins, chemicals linked to improved mood, while maintaining a regular sleep schedule helps stabilize the body's internal clock. A clean and comfortable living environment reduces stress signals processed by the brain. That is one reason cleaning rooms and improving ventilation become especially important during the humid rainy season.
People often think of emotions as matters of the mind alone. Yet the discomfort associated with the monsoon is a scientific phenomenon created by interactions among the brain, the body and the surrounding environment. We cannot change the weather, but we can influence how our brains respond to it. Turning on a light, opening a window or taking a brief walk are all small actions that can make a meaningful difference.
The monsoon itself is unavoidable, but the human brain is far more adaptable than many people realize. During the rainy season, simple daily habits can help preserve emotional balance, reminding us that even when the skies remain gray we still have the ability to create clearer weather within ourselves.
This article was originally written in Korean and translated by a bilingual reporter with the help of generative AI tools. It was then edited by a native English-speaking editor. All AI-assisted translations are reviewed and refined by our newsroom.
