Staying Healthy in Summer: Heat Waves, Tropical Nights, and Mosquitoes Guide

Korean summers are hot and humid, making it easy to fall ill. Heat waves, tropical nights, and mosquito-borne diseases that spike during the rainy season are all real risks — but knowing about them in advance can go a long way toward keeping you and your family safe. According to the Korea Disease Control and Prevention Agency (KDCA), the number of heat-related illness cases rose steadily over the five years from 2020 to 2024, with 80.1% of those cases occurring outdoors in places such as fields and farms. Please read through the information below before the heat arrives.

What Are Heat Waves and Tropical Nights?

The Korea Meteorological Administration issues the following official alerts based on the severity of the heat.

You can check real-time heat wave alerts on the Korea Meteorological Administration’s special weather report page. Before heading out, you can also confirm the latest weather information through 1345 (Immigration Contact Center, available in multiple languages) or your local public health center.

Health Guidelines for Heat Waves and Tropical Nights

The KDCA recommends three core principles for preventing heat-related illness: water, shade, and rest.

Managing Food and Fluid Intake

• Avoid strenuous exercise during the hottest part of the day (10 a.m. to 5 p.m.).
• Limit caffeine (coffee, energy drinks) and alcohol, as both draw moisture out of your body. Drink water frequently instead.
• Eat balanced meals, but do not leave food sitting out for long periods.
• Boil your drinking water when possible, and try to avoid raw foods such as raw seafood and unwashed vegetables.

Managing Your Indoor Environment

• Try to keep the temperature difference between indoors and outdoors within about 5°C (9°F). Moving suddenly between strongly air-conditioned spaces and hot outdoor air puts a significant strain on the body.
• Ventilate your home regularly to keep the air circulating.
• When a heat wave warning is in effect, you can use a nearby “cooling shelter” (무더위쉼터) — these are designated public spaces such as community centers, senior centers, and libraries that are open and air-conditioned during extreme heat. People with a foreign registration card are welcome to use them. You can find the nearest one through the Ministry of the Interior and Safety’s National Disaster Safety Portal.

Sleep and Daily Habits

• Wear light, loose-fitting clothing.
• Try to go to sleep and wake up at consistent times.
• Do light exercise regularly, but choose the morning or evening rather than the middle of the day.
• Before going to bed, shower with lukewarm water rather than cold water. Cold water can actually disrupt blood circulation.
• Avoid looking at TV or smartphone screens right before bed.
• If you live alone, check in on your neighbors from time to time.

If you are having ongoing trouble sleeping, the article on causes and prevention of sleep disorders, self-assessment, and hospital guidance may also be helpful.

Types of Heat-Related Illness and First Aid

Heat-related illnesses are acute conditions caused by exposure to high temperatures. Prolonged time in a hot environment can lead to headaches, dizziness, muscle cramps, fatigue, and loss of consciousness — and if left untreated, these conditions can be life-threatening. The conditions are categorized as follows. You can also find detailed information on the KDCA’s heat-related illness information page.

Heat Cramps

Heat cramps occur when the body becomes deficient in salt (sodium), potassium, or magnesium, leading to muscle spasms. They are especially likely when doing heavy physical labor or exercise in a hot environment.

Symptoms: Sweating along with pain or cramping in the legs or abdominal muscles.

First aid:

• Move to a cool place and rest.
• Replenish fluids with water or a sports drink. Sports drinks can be helpful if you have been sweating heavily, but be aware that some have a high sugar content.
• Gently massage the cramping muscle. Even after the cramp stops, do not immediately return to work — take adequate rest first.
• If cramps persist for more than an hour, or if you have an underlying condition such as heart disease, go to an emergency room immediately.

If you feel nauseous or begin vomiting, do not force yourself to drink water — go to the hospital right away.

Heat Exhaustion

Symptoms: Sweating with cool, clammy skin; dizziness; and a feeling of weakness or lethargy.

First aid:

• Move to a cool location and loosen any tight clothing.
• If the person is conscious, have them sip water slowly.
• If vomiting occurs, go to a hospital immediately.

Heat Stroke

A person experiencing heat stroke may not be aware of how sharply their body temperature has risen. Their skin becomes hot and flushed, and their heart rate and breathing rate increase. Impaired brain function can cause confusion, disorientation, seizures, or even loss of consciousness.

Symptoms: High body temperature, rapid pulse, dizziness, and confusion or loss of consciousness.

First aid:

• A heat stroke patient must be cooled down immediately, and an ambulance must be called. Call 119 right away.
• Move the person to a shaded, cool area and loosen their clothing.
• If immersion in water is not possible, spray water over the body and use a fan to blow air over the entire body to lower the temperature.
• If the person is unconscious, never try to give them water to drink.

Mosquito Prevention

During the rainy season, standing water accumulates easily, causing mosquito populations to surge. Mosquito bites can lead to more than just itching — serious infections such as malaria and Japanese encephalitis are also a risk, so thorough prevention is important. For detailed information on mosquito-borne diseases, visit the KDCA Infectious Disease Portal.

Managing Your Indoor and Outdoor Environment

• Check your window screens for holes and repair any you find.
• Make sure water cannot collect in containers such as basins, plant pot trays, and glass bottles, both inside and outside your home. Standing water is an ideal breeding environment for mosquito larvae.
• Spray insecticide around drains, near your front door, and on the outer walls around your entrance to help prevent mosquitoes and other pests from getting in.

Precautions for Outdoor Activities

• When outdoors, avoid using perfume or strongly scented cosmetics. Fragrance can attract mosquitoes.
• Use insect repellent when spending time in areas with lots of grass or trees.

Special Precautions for Infants and Young Children

• Do not use insect repellent on infants under 6 months of age. For children under 2 years old, avoid products containing DEET, and always check the age guidelines on the product label.
• When applying repellent to a young child, first spray a small amount onto an adult’s hands, then gently apply it to the child’s skin.
• Try to prevent young children from spending time outdoors during the evening hours when mosquitoes are most active.

Borrowing Self-Disinfection Equipment from Your Local Public Health Center

If you would like to disinfect the area around your home yourself, you can contact your local public health center (보건소) to ask whether self-disinfection equipment is available to borrow and how to apply. Before applying, check with 1345 or the Korea Immigration Service (출입국·외국인청) for the most current information.

Emergency Contact Numbers

During the hot summer months, please pay attention to how your own body is feeling — and take a moment to check in on your neighbors as well.