Extreme heat and valley fever: health when travelling to Phoenix, Las Vegas and Palm Springs

The American Southwest seduces with pools, near-guaranteed sun and mild evenings, but its climate and soil pose health risks that travellers underestimate. This guide summarises what the US Centers for Disease Control and Prevention (CDC) say, checked on 7 November 2026, and adapts it to couples who plan to go out at night. It is no substitute for medical advice: if you have a chronic illness or take medication, talk to your doctor before travelling.

Heat is not a detail

The CDC notes that hot days can affect anyone, although pregnant people, children and teens with asthma, people with heart conditions or other chronic illnesses, older adults, outdoor workers, athletes, and infants and young children are at higher risk. Many medicines can cause dehydration or overheating, and some need protecting from heat. Symptoms of overheating include muscle cramps, unusually heavy sweating, shortness of breath, dizziness, headache, weakness and nausea. If they are severe or worsening, seek medical care without delay.

How to prevent it, according to the CDC

Stay cool. Outdoors on a high-risk day, stay in the shade, take breaks and schedule activity for the coolest parts of the day. Indoors, use fans only if the temperature is below 90 °F (about 32 °C); otherwise use air conditioning or a cooling centre.

Stay hydrated. Carry water and drink throughout the day. Limit sugary or salty drinks, caffeine and alcohol. Clear or light-yellow urine suggests good hydration.

Plan ahead. Check the CDC HeatRisk dashboard and air quality, talk to your doctor before changing medicines, and have a backup plan for refrigerated medication and medical devices in a power cut.

Look after others. Check on the people you travel with.

Valley fever: what it is and where it occurs

Valley fever, or coccidioidomycosis, is an infection caught by inhaling spores of the Coccidioides fungus, which lives in soil. According to the CDC it occurs in the southwestern US and south-central Washington state, as well as parts of Mexico, Central America and South America. It does not spread from person to person or between people and animals. Some people never get sick; others have fatigue, cough, fever and headache, shortness of breath, night sweats, muscle or joint aches, or a rash on the upper body or legs. Between 5 and 10 % develop serious or long-term lung problems, and around 1 % have an infection that spreads to the skin, bones, joints or brain. The CDC warns that it is often mistaken for bacterial or viral pneumonia and recommends getting evaluated: early antifungal treatment can save lives in severe cases.

What it means for your trip

If you are heading to Phoenix, Las Vegas, Palm Springs or the Californian desert, plan the day to avoid the central hours, carry water everywhere and skip strenuous exercise at midday. If you come home with a persistent cough, fever or fatigue, tell your doctor where you have been: it can be a decisive clue for the diagnosis. By the pool and at night, remember that alcohol worsens dehydration.

Going out at night in the heat

If you plan to visit a club or party, apply the hydration rule: water between drinks, food before you go out and a safe way home. At Club Joi parties, for example, hours run until 5 am: do not start the night dehydrated. More preparation ideas in our couples’ travel guide and, for local rules, in the nudity law guide.

Quick checklist before you leave

Before heading to the airport, check five things: the official forecast at weather.gov and the CDC HeatRisk dashboard for your dates; that your medicines can cope with the heat of a car or suitcase (ask your pharmacist if they need refrigeration); that your travel insurance covers medical care in the United States, where an emergency visit can be very expensive; that you know how to reach a medical centre from your lodging; and that you have talked with your partner about what to do if one of you feels unwell in the middle of a party: leaving without explanations or guilt is a basic rule of the scene.

Where to read on

The destinations for Phoenix, Las Vegas and Palm Springs carry more practical context.

Frequently asked questions

Is valley fever contagious? No: according to the CDC it does not spread between people or between people and animals.

Which heat symptoms are urgent? If they are severe or worsening, seek medical care; the CDC lists cramps, heavy sweating, shortness of breath, dizziness, headache, weakness and nausea.

How much water should I drink? The CDC gives no figure: it advises drinking throughout the day and watching urine colour.

What if I come back with a cough and fever? See a doctor and mention that you travelled to the US Southwest.