Supporters travelling to the World Cup are being warned to brace for intense heat, with health professionals stressing the need to stay alert to the dangers of heat-related illness.
The concern is not just anecdotal. Recent research on the 2026 FIFA World Cup found that 14 of the 16 host locations are likely to exceed a wet-bulb globe temperature (WBGT) of 28C, a widely used threshold for dangerous heat stress that takes account of temperature, humidity, sun exposure and wind. The tournament is being staged across 16 host cities in the US, Canada and Mexico from June 11 to July 19, putting many supporters outdoors during some of the hottest weeks of the North American summer.
Researchers have found that 14 of the 16 host locations being used for the tournament are likely to experience what they describe as dangerous temperatures, with conditions expected to rise well above 80°F.
In light of that, Dr Donald Grant, GP and Senior Clinical Advisor at The Independent Pharmacy, has set out the potential risks facing fans who spend long periods outdoors in soaring temperatures.
“As fans from all over the world travel to the US for the World Cup, it’s vital that they understand the dangers associated with prolonged periods in sweltering heat.
“Some forecasts are suggesting temperatures as high as 40 degrees Celsius, increasing the risk of heat-related illnesses, such as heat exhaustion, heatstroke, dehydration and severe sunburn.
“During match days, when fans spend long periods in direct sunlight, during queuing or travelling to football stadiums, this can further heighten the risk of these illnesses.”
Heat can become especially dangerous when humidity is high, because sweat does not evaporate as efficiently and the body struggles to cool itself. That is one reason experts use WBGT rather than air temperature alone when assessing risk at major outdoor events. Scientists who have studied the World Cup schedule have also warned that afternoon kick-offs in cities such as Miami, Dallas, Kansas City, Atlanta and Monterrey may pose a greater heat burden than evening matches.
He also warned that drinking alcohol, something likely to be common during the tournament, can make matters worse by speeding up dehydration and intensifying symptoms.
US public health guidance also advises limiting alcohol, caffeine and very sugary drinks during extreme heat, as they can make it harder to stay properly hydrated. Fans should aim to drink water regularly through the day rather than waiting until they feel thirsty, and should take every opportunity to cool down in shade or air-conditioned spaces before and after matches.
Dr Grant said it is especially important for fans to understand the difference between heat exhaustion and the more serious threat of heatstroke.
“Heat exhaustion is typically the first sign that the body is struggling to cope in the heat,” he added.
“Symptoms include dizziness, headaches, heavy sweating and weakness. If it’s not addressed promptly, it can quickly develop into heatstroke.
“Heatstroke occurs when the body is no longer able to control its temperature. In extreme cases, it can lead to seizures and organ damage, so it should never be ignored.”
According to the US Centers for Disease Control and Prevention, warning signs of heat exhaustion can include heavy sweating, cold, pale or clammy skin, muscle cramps, tiredness, weakness, dizziness, headache, nausea or fainting. Heatstroke is a medical emergency, and symptoms can include confusion, slurred speech, loss of consciousness, seizures, a very high body temperature and either hot, dry skin or profuse sweating.
If symptoms do appear, he advised people to ‘replace lost fluids with adequate hydration’.
First aid matters too. Anyone with suspected heat exhaustion should be moved to a cooler place, have excess clothing loosened or removed, and be cooled with cold cloths, fans or cool water while sipping fluids if they are fully alert. If symptoms get worse, last longer than about an hour, or the person vomits or becomes confused, urgent medical help should be sought. If heatstroke is suspected, call emergency services immediately and begin rapid cooling while waiting for help.
He further urged younger supporters, older people and those with pre-existing medical conditions to ‘take further caution’ when dealing with extreme heat.
People at higher risk can include older adults, infants and children, pregnant women, people with heart disease, diabetes or kidney problems, and anyone taking medicines that affect hydration or the body’s ability to regulate temperature. Travellers arriving from cooler climates may also be more vulnerable because they are not acclimatised to the heat.
“Fans should also look out for changes in behaviour, particularly in friends or family members who may not realise how unwell they are becoming. Cognitive changes, including confusion, slurred speech and disorientation, can often be signs of heatstroke.”
His overall advice is for supporters to avoid overdoing alcohol and keep drinking plenty of water throughout the day, including during the match itself.
FIFA has already acknowledged the issue on the playing side, confirming three-minute hydration breaks in each half of every World Cup 2026 match regardless of venue or temperature. For supporters, the practical message is similar: check local forecasts before travelling, wear loose and light-coloured clothing, use sunscreen, rest in shaded or air-conditioned areas when possible, and act quickly at the first sign that the heat is becoming too much.