April is traditionally one of the hottest months in Thailand. And even though forecasters aren't expecting record temperatures in Phuket this year, an ordinary April is still plenty hot. According to the Phuket Meteorological Center, air temperatures will reach 38–40°C in the shade, and with weak winds and high humidity factored in, the Heat Index will climb as high as 54°C.
If you've never heard of the Heat Index, it's a measure that doesn't track air temperature in the usual sense, but rather how the human body actually perceives that temperature — primarily accounting for humidity. For this April's heat, Thailand's Ministry of Public Health uses a four-tier scale:
Heat Index:
27–32°C: Moderate heat. The body handles it without issue.
32–41°C: Intense heat. Overheating and heatstroke become possible with prolonged sun exposure.
41–54°C: High danger. The risk of heatstroke rises sharply; maximum caution is required.
Above 54°C: Extreme danger. Heatstroke is inevitable, with possible serious health consequences and even death.
Since February, Phuket's Heat Index has consistently sat in the second and third zones, edging toward extremely dangerous levels. Most heatstroke deaths, meanwhile, happen in April.
Safety in the car
April's temperatures worry doctors, meteorologists, firefighters, and staff at plenty of other agencies. Every year the Department of Disaster Prevention and Mitigation (DDPM) reminds people that a cigarette tossed into dry grass in this kind of weather can turn into a real disaster. Fires like this often break out along roadsides, since a driver, unlike a pedestrian, can't stamp out a cigarette underfoot.
The Department of Land Transport (DLT) issues its own heat warnings too, specifically asking drivers not to leave items in their vehicles that could spoil or even catch fire in the heat.
Don't leave in your car:
It should go without saying that pets or children should never be locked in a car in this heat. The only thing worth adding is that there's no safe duration for this — any "just a few minutes" can unpredictably stretch on.
Safety outdoors
Doctors keep repeating that beyond sunburn (from direct sun exposure), April heat also brings a high risk of heatstroke — a risk that stays high even in the shade or indoors, if there's no air conditioning. Heatstroke is a serious health danger.
Signs of heatstroke:
First aid for heatstroke:
Protecting yourself from heatstroke:
Older adults, children, and people with chronic conditions deserve special attention during this period. Timely precautions and simply following these recommendations can make all the difference in getting through this extremely hot stretch without harm. Take care of yourself and the people around you, and stay alert and careful on the hottest days of the year.
If you've never heard of the Heat Index, it's a measure that doesn't track air temperature in the usual sense, but rather how the human body actually perceives that temperature — primarily accounting for humidity. For this April's heat, Thailand's Ministry of Public Health uses a four-tier scale:
Heat Index:
27–32°C: Moderate heat. The body handles it without issue.
32–41°C: Intense heat. Overheating and heatstroke become possible with prolonged sun exposure.
41–54°C: High danger. The risk of heatstroke rises sharply; maximum caution is required.
Above 54°C: Extreme danger. Heatstroke is inevitable, with possible serious health consequences and even death.
Since February, Phuket's Heat Index has consistently sat in the second and third zones, edging toward extremely dangerous levels. Most heatstroke deaths, meanwhile, happen in April.
Safety in the car
April's temperatures worry doctors, meteorologists, firefighters, and staff at plenty of other agencies. Every year the Department of Disaster Prevention and Mitigation (DDPM) reminds people that a cigarette tossed into dry grass in this kind of weather can turn into a real disaster. Fires like this often break out along roadsides, since a driver, unlike a pedestrian, can't stamp out a cigarette underfoot.
The Department of Land Transport (DLT) issues its own heat warnings too, specifically asking drivers not to leave items in their vehicles that could spoil or even catch fire in the heat.
Don't leave in your car:
- Power banks
- Electronic devices (smartphones, tablets, laptops)
- Aerosol cans
- Lighters and containers of flammable chemicals
- Rubber mats and plastic items that melt easily
- Medications
It should go without saying that pets or children should never be locked in a car in this heat. The only thing worth adding is that there's no safe duration for this — any "just a few minutes" can unpredictably stretch on.
Safety outdoors
Doctors keep repeating that beyond sunburn (from direct sun exposure), April heat also brings a high risk of heatstroke — a risk that stays high even in the shade or indoors, if there's no air conditioning. Heatstroke is a serious health danger.
Signs of heatstroke:
- Body temperature rising to 40°C or higher
- Hot, dry skin — or, conversely, excessive sweating
- Headache and a feeling of confusion
- Nausea, vomiting, severe weakness
- Rapid heartbeat and breathing
- Loss of consciousness or seizures
First aid for heatstroke:
- Move the person immediately into shade or a cool, well-ventilated space.
- Remove or loosen clothing to allow air to circulate freely.
- Cool the body with a damp cloth or cold water, paying particular attention to the head, neck, armpits, and groin.
- If the person is conscious, give them small sips of water.
- If unconscious, lay the person on their side to keep the airway clear and prevent the tongue from blocking it.
- Call emergency medical services immediately at 1669.
Protecting yourself from heatstroke:
- Stay in air-conditioned spaces or in the shade between 11:00 a.m. and 4:00 p.m., the hottest part of the day.
- Wear light-colored, loose clothing, ideally made of natural fabric.
- Use sunscreen with a high SPF.
- Wear sunglasses and a hat.
- Drink plenty of water, avoiding ice-cold drinks — sudden temperature swings are hard on the cardiovascular system.
- Avoid alcohol, since it worsens dehydration.
- Never leave children or pets in a car, even briefly — cabin temperatures rise to life-threatening levels shockingly fast.
- Carry drinking water on trips, and stop as soon as you notice signs of fatigue or overheating.
Older adults, children, and people with chronic conditions deserve special attention during this period. Timely precautions and simply following these recommendations can make all the difference in getting through this extremely hot stretch without harm. Take care of yourself and the people around you, and stay alert and careful on the hottest days of the year.
What You Need to Know
The Heat Index Is Heating Up
Original text translated by Claude