Many road trips to the Grand Canyon include a short walk below the rim.
It is easy to see why.
A few steps down a trail, the crowds fade and the canyon opens up around you.
Canyon hiking has a trap that catches many visitors.
The hike starts downhill, so the first part feels easy.
The hard part, the climb back up, comes when you are already tired and the day is hotter.
The National Park Service warns that scores of unprepared hikers suffer severe illness, injury or death every year.
Many were lured by the easy downhill start.
This guide explains how to plan a safer canyon hike as part of a road trip.
It is based on guidance from Grand Canyon National Park.
It is general information, not medical advice.
An upside-down hike
On a mountain, you climb first and come down tired.
In a canyon, it is the other way around.
You descend while fresh and cool, then climb out in the heat of the day.
Plan your turnaround point with that in mind.
Many hikers use a simple rule of thumb: allow about twice as long to come back up as it took to go down.
Turn around well before you feel tired, not when you are already worn out.
Walking farther down is optional, but the climb back to your car is not.
The canyon gets hotter as you descend
The rim can feel pleasant while the inner canyon is dangerously hot.
On its Hike Smart page, the park urges caution for all hikers from May through September.
It notes that the farther into the canyon you go, the hotter it gets.
Summer daytime temperatures in the inner canyon can exceed 110°F, or 43°C.
The park publishes average shade temperatures at Phantom Ranch, near the canyon floor.
In July, the average high there is 104°F in the shade.
The park adds that temperatures in full sun can be 20 to 30°F warmer than posted shade temperatures.
Avoid hiking from 10 am to 4 pm
The park's clearest advice is about timing.
It asks hikers to avoid hiking in direct sun between 10 am and 4 pm in summer.
Most people who need emergency help for heat illness in the canyon were hiking during those hours.
The park calls timing the most important factor in avoiding hazards.
On a road trip, that can feel inconvenient.
You may arrive at the rim at midday after a long drive.
Use that time for viewpoints, the visitor center and lunch in the shade instead.
- Start a summer hike before sunrise, after a night near the park.
- Or start in the late afternoon and finish before dark.
- Rest in shade near water during the hottest hours if you are already below the rim.
Carry a flashlight and spare batteries.
The park warns not to rely on your phone as a light source.
Water is not everywhere
Do not count on finding water on the trail.
The park notes that only the Bright Angel and North Kaibab Trails have drinking water spigots.
Those may be out of service at times, because of the season or maintenance.
The South Kaibab Trail has no water sources and minimal shade.
The park calls hiking up it in summer extremely strenuous and potentially dangerous.
Before any hike, check the park's current trail messages for water availability and heat risk.
Carry plain water and some form of electrolyte replacement.
Water and salt work together
Hydration in the canyon is about balance, not just volume.
The park says hikers can lose one or two quarts, or liters, of water per hour.
In the dry air, sweat evaporates quickly, so you may not notice how much you lose.
Salt stains or rings on your clothing are a common sign.
The park advises sipping water regularly and resting and eating often.
Its headline advice is not to force fluids, and to drink when you are thirsty.
Salty food matters as much as water.
The park suggests salty snacks like pretzels, crackers and chips.
It even advises eating about twice as much as you normally would.
Three conditions to know
The park lists three heat-related problems that every canyon hiker should recognize.
Heat exhaustion. This comes from dehydration due to heavy sweating.
Symptoms include fatigue, nausea, vomiting, cool and moist skin, headache and cramps.
The park's advice is to stop hiking and rest in the shade for 30 to 45 minutes.
Drink water with electrolytes, eat high-energy food and cool the body by getting wet.
Heat stroke. This is a life-threatening emergency.
The body loses its ability to cool itself.
Signs include a flushed face, dry skin, a weak and rapid pulse and a high body temperature.
The key difference from heat exhaustion is a change in mental state.
Watch for confusion, poor judgment, unconsciousness or seizures.
The park says to cool the person immediately and call for help.
Keep pouring water on the head and body, fan them and move them into shade if possible.
Hyponatremia. This is low sodium in the blood.
It happens when someone drinks too much water while losing salt through sweat.
Early symptoms look like heat exhaustion: fatigue, nausea and vomiting.
Other signs include confusion and frequent urination, and the person may seem intoxicated.
The park advises stopping water, eating salty food and resting in the shade.
If mental alertness gets worse, seek help immediately.
This is why salty snacks are not optional on a hot canyon hike.
Stay wet to stay cool
The park recommends a simple cooling trick: keep yourself soaking wet.
Whenever you reach water, soak your clothing, hat or bandana.
It notes that cotton, which holds water well, works well in the desert.
Spray bottles, bandanas and small towels are easy ways to cool off between water sources.
Help may be slow to arrive
The canyon is not a city park.
The park warns that rescue can be delayed by limited staff and the number of calls.
Extreme heat and bad weather can also limit helicopter flights.
When hiking in the inner canyon, the park says self-rescue is required.
That means carrying enough water, food and first aid supplies.
It also means knowing your limits and having a plan to get back to the rim.
Health conditions and the canyon
Heat, steep grades and long climbs strain even healthy people.
The park notes that pre-existing medical conditions can get much worse in these conditions.
If you have a health condition, it strongly recommends talking with your doctor before a rigorous hike.
Ask specifically about hot weather and steep climbing.
What to pack for a short canyon hike
The park's summer list is a good starting point, even for a short walk.
- Plain water and an electrolyte replacement.
- Salty snacks and high-energy food.
- A first-aid kit with blister care.
- A map, even on a well-marked trail.
- Sturdy, broken-in shoes with good traction.
- A flashlight and spare batteries.
- A hat, sunscreen and sun-protective layers.
- A spray bottle, bandana or towel for cooling.
- A whistle or signal mirror for emergencies.
- A rain jacket or poncho during monsoon season, from mid-July to early September.
Our guide to sun protection on a road trip covers skin and eye protection in more detail.
Fit the hike into your road trip
A few planning choices make canyon hiking much safer.
- Stay near the park the night before so you can start at dawn.
- Do not plan a hike on the same day as a long drive.
- Pick a turnaround time before you start, and keep it.
- Leave a cooler with water and salty food in the car for the end.
- Tell someone your trail and expected return time.
Our guide to desert road trips covers heat on remote roads between parks.
For reservations and the essentials, see our national park road trip planning guide.
The bottom line
The Grand Canyon is an upside-down hike: easy down, hard up.
In summer, avoid hiking from 10 am to 4 pm and turn around early.
Carry water, electrolytes and salty food, and know the signs of heat illness and hyponatremia.
Plan to rescue yourself, and the climb back to your car will be part of a great day.
Sources and Further Reading
- National Park Service, Grand Canyon National Park: Summer Hiking, Hike Smart — supports the summer caution period, inner canyon temperatures, the Phantom Ranch shade averages, the 10 am to 4 pm advice, water sources on each trail, fluid and salt advice, the heat exhaustion, heat stroke and hyponatremia guidance, staying wet, self-rescue and the packing list.
- National Park Service: Trip Planning Guide — supports researching trail conditions and park rules before your visit.