Heat at Outdoor Events: Hydration, Shade and Warning Signs

A summer festival, an afternoon ballgame or a long tailgate can mean hours in the sun with little shade and a lot of standing. The CDC says hot days can affect anyone. Some people face more risk than others, including older adults, young children, pregnant people, people with chronic conditions and anyone exerting themselves outdoors.

Heat illness is mostly preventable with planning, and the warning signs are easy to learn. This guide pulls together official guidance from the CDC, NIOSH and the National Weather Service so you can enjoy the day and know when to act.

This is general safety information, not medical advice. If you have a health condition or take regular medication, ask your doctor how heat affects you. In an emergency, call 911.

Check the forecast the right way

Air temperature alone doesn't tell you how hard a day will be on your body. Two National Weather Service tools help:

• Heat index measures how hot it really feels when humidity is factored in. In the NWS example, an air temperature of 96°F with 65% relative humidity gives a heat index of 121°F. The NWS also says heat index values assume shade and light wind, and full sunshine "can increase heat index values by up to 15°F." That matters if your seats or the festival field have no shade.
• HeatRisk gives each location a color and number for the level of heat concern over the next seven days. It considers how unusual the heat is for that place and time of year, and whether nights stay warm. The NWS labels HeatRisk experimental. The CDC's heat guidance points people to its HeatRisk dashboard, searchable by ZIP code.

Check both for the event location, not just your home, and look at the hours you'll actually be outside.

Hydrate before you're thirsty

The CDC's hydration advice for hot days is simple:

• Drink plenty of fluids. Carry a water bottle and refill it throughout the day.
• Consider limiting drinks high in sugar or sodium, caffeine and alcohol.
• Check your urine color. Light yellow or clear usually means you're drinking enough.

For people who are physically active in heat, the CDC adds: "don't wait until you're thirsty to drink more." A day of walking between stages or climbing stadium ramps counts.

Before you pack a bottle, check the venue's rules. They vary a lot. For example, as of October 2026, the Minnesota Twins allow only sealed bottled water of 32 ounces or less and certain children's drinks at Target Field, and they don't allow flavored or sports drinks. Other venues, festivals and concerts set their own rules, which may be stricter or looser. If outside water isn't allowed, find the water fountains or refill stations on the venue map when you arrive.

If your doctor limits your fluids or you take water pills, the CDC says to ask how much you should drink during hot weather.

Shade, timing and what to wear

The CDC's heat guidance suggests staying in the shade as much as possible, taking breaks when you can, and doing outdoor activities during the coolest parts of the day if possible. At an event, that can mean:

• Arriving later or leaving the hottest stretch of the afternoon for an indoor concourse, a shaded tent or a cooling area.
• Taking regular breaks from standing in direct sun, especially near crowded stages.
• Choosing seats or a viewing spot with shade when you have the option.

For sun protection, the CDC recommends broad-spectrum sunscreen with SPF 15 or higher, reapplied if you're out more than 2 hours and after swimming, sweating or toweling off. It also recommends a hat with a brim all the way around, sunglasses that block UVA and UVB rays, and tightly woven clothing. It notes that UV rays are strongest from 10 a.m. to 4 p.m. daylight saving time in the continental U.S. For children, the CDC suggests loose, lightweight, light-colored clothing.

Know the warning signs

The CDC lists symptoms of overheating that can include muscle cramping, unusually heavy sweating, shortness of breath, dizziness, headache, weakness and nausea. NIOSH separates the main heat illnesses this way:

• Heat cramps: muscle cramps or spasms after heavy sweating. NIOSH advises water plus a snack or sports drink that replaces carbohydrates and electrolytes, and avoiding salt tablets. Get medical help if cramps don't ease within an hour, or if the person has heart problems or is on a low-sodium diet.
• Heat syncope: fainting or dizziness, often from standing too long or standing up suddenly. Sit or lie down somewhere cool and slowly drink water, clear juice or a sports drink.
• Heat exhaustion: headache, nausea, dizziness, weakness, irritability, thirst, heavy sweating, elevated body temperature and decreased urine output. Move out of the heat, remove extra clothing, cool the skin with cold compresses or cold water, encourage frequent sips of cool water, and get medical evaluation. Have someone stay with the person.
• Heat stroke: the most serious. NIOSH lists confusion, slurred speech, loss of consciousness, hot dry skin or profuse sweating, seizures and very high body temperature. It says body temperature can rise to 106°F or higher within 10 to 15 minutes.

If someone may have heat stroke

Heat stroke is a medical emergency. NIOSH's first aid steps are:

1. Call 911, and stay with the person until help arrives.
2. Move them to a shaded, cool area and remove outer clothing.
3. Cool them quickly: a cold water or ice bath if possible, wet skin, cold wet cloths, or clothing soaked in cool water.
4. Circulate air around them, and place cold wet cloths or ice on the head, neck, armpits and groin.

At a venue, also alert the nearest staff member or send someone to the first aid station so on-site medical staff can find you.

Extra care for kids, older fans and medications

• Children: the CDC says never leave infants or children in a parked car, even with a window cracked. Temperatures inside can rise almost 20°F in the first 10 minutes. That applies to tailgates and festival parking lots too.
• Older adults: the CDC notes that people 65 and older don't adjust as well to sudden temperature changes and are more likely to take medicines that affect temperature control or sweating.
• Medications: the CDC says many medicines can make you dehydrated or overheated on hot days, and some need to be kept out of hot places. Don't stop or change a medicine without talking to your doctor. Plan how you'll keep any medicines cool.
• Everyone: watch your group. The CDC advises people active in heat to monitor each other's condition.

Key takeaways

• Check the heat index and HeatRisk for the event location. Full sun can make conditions feel up to 15°F hotter than the heat index.
• Drink fluids throughout the day without waiting for thirst, and check the venue's water bottle rules before you pack.
• Use shade, breaks, a brimmed hat and SPF 15+ broad-spectrum sunscreen, reapplied after 2 hours or after sweating.
• Learn the signs of heat exhaustion and heat stroke. Confusion, slurred speech or fainting means call 911 and start cooling.
• Never leave children in a parked car, and plan ahead for older fans and anyone on medication.

Sources

• CDC, About Heat and Your Health (July 20, 2026)
• CDC, Heat and Athletes
• CDC, Infants and Children and Heat (June 25, 2024)
• CDC, Heat and Older Adults (Aged 65+)
• NIOSH, Heat-related Illnesses (March 3, 2026)
• National Weather Service, Heat Forecast Tools
• CDC, Sun Safety
• Minnesota Twins, Target Field Policies and Procedures